Find a PhD Project Here
Opportunities for fully funded PhD or EngDoc research projects are available in all fields of research within the School. You may search for current projects on this page. APPLY HERE for a PhD Place.
For UK students and a limited number of European students, UK Research Council funding (EPSRC and STFC) is available to cover both fees and stipend; successful applicants for PhD or EngDoc study will normally have a first or upper-second class degree in physics, astronomy, or related subject.
There are several other funding mechanisms open to UK, EU and international students. These include the prestigious SUPA Prize Studentships and specific research projects with embedded studentships. International students may also consider applying for Commonwealth Scholarships, other National Scholarships or a joint PhD programme with an overseas university such as Cotutelle internationale de these.
You may alternatively apply to a discipline-specific Doctoral Training Centre in Condensed Matter Physics, in Magnetic Resonance, or an Engineering Doctorate in Photonics.
Search current PhD opportunities in the School of Physics & Astronomy:-
Astrophysics
Annihilation of Dark Matter
Zhao, Dr Hongsheng - hz4@st-andrews.ac.uk
A main diagnostic of the particle dark matter is its annihilation rate, which depends sensitively on the dark matter density profile. The student will explore various density models of the dark matter, taking into account the effects of black holes and baryonic dynamics.
A main diagnostic of the particle dark matter is its annihilation rate, which depends sensitively on the dark matter density profile. The student will explore various density models of the dark matter, taking into account the effects of black holes and baryonic dynamics.
Atmospheres of Very Low Mass Objects: Brown Dwarfs and giant gas planets
Helling, Dr Christiane - ch80@st-andrews.ac.uk
These projects will investigate the atmospheres of planets and Brown Dwarfs which contain the fingerprints of their physics and chemistry. Atmospheres of Brown Dwarfs and giant gas planets are forming clouds that can be made of silicate and iron dust rather than of water. Any clouds leave a trace of an individually depleted gas which determines the spectral appearance of the planet/Brown Dwarf as well as it does influence the dynamic behaviour of the atmosphere.
Using a detailed model of dust formation, possible topics include:
1) Atmosphere's response on planetary evolutionary events
like volcanism, dust/gas accretion, mass loss during star-planet interaction
2) Modeling atmospheres of planets/Brown Dwarfs in nearby galaxies,
like the Large and the Small Magellanic Cloud
3) Modeling planetary atmospheres under the influence of disk evolution
combining results from protoplanetary disk evolution model with atmosphere modeling
These projects will investigate the atmospheres of planets and Brown Dwarfs which contain the fingerprints of their physics and chemistry. Atmospheres of Brown Dwarfs and giant gas planets are forming clouds that can be made of silicate and iron dust rather than of water. Any clouds leave a trace of an individually depleted gas which determines the spectral appearance of the planet/Brown Dwarf as well as it does influence the dynamic behaviour of the atmosphere.
Using a detailed model of dust formation, possible topics include:
1) Atmosphere's response on planetary evolutionary events
like volcanism, dust/gas accretion, mass loss during star-planet interaction
2) Modeling atmospheres of planets/Brown Dwarfs in nearby galaxies,
like the Large and the Small Magellanic Cloud
3) Modeling planetary atmospheres under the influence of disk evolution
combining results from protoplanetary disk evolution model with atmosphere modeling
Charge separation in turbulent volcano plumes
Helling, Dr Christiane - ch80@st-andrews.ac.uk
We will study the charge separation and lightning processes in volcano plumes. The results will help us to understand the electrification of extrasolar atmospheres.
see also LEAP PhD positions
We will study the charge separation and lightning processes in volcano plumes. The results will help us to understand the electrification of extrasolar atmospheres.
see also LEAP PhD positions
Coronal structure of low mass stars
Cameron, Prof Andrew - acc4@st-andrews.ac.uk
Jardine, Prof Moira - mmj@st-andrews.ac.uk
Low mass (fully convective) stars appear to generate magnetic fields whose surface distributions are fundamentally different to those of higher mass stars. We will use existing Zeeman-Doppler maps of these surface magnetic fields to model the coronal structure and X-ray emission of these stars.
Jardine, Prof Moira - mmj@st-andrews.ac.uk
Low mass (fully convective) stars appear to generate magnetic fields whose surface distributions are fundamentally different to those of higher mass stars. We will use existing Zeeman-Doppler maps of these surface magnetic fields to model the coronal structure and X-ray emission of these stars.
Diffuse ionized gas in galaxies
Wood, Dr Kenneth - kw25@st-andrews.ac.uk
Extensive layers of diffuse ionized gas are observed in the Milky Way and other galaxies. This project will study the structure, ionization, heating, and dynamics of diffuse ionized gas using a combination of 3D Monte Carlo radiation transfer codes and recent 3D dynamical models of a supernova driven ISM.
Extensive layers of diffuse ionized gas are observed in the Milky Way and other galaxies. This project will study the structure, ionization, heating, and dynamics of diffuse ionized gas using a combination of 3D Monte Carlo radiation transfer codes and recent 3D dynamical models of a supernova driven ISM.
Echo Mapping of AGN
Horne, Prof Keith - kdh1@st-andrews.ac.uk
Light travel time delays enable micro-arcsecond mapping of accretion disks and broad emission-line regions around the super-massive black holes in the nuclei of active galaxies. RoboNet provides the UK with unique datasets for measurement of black hole masses, accretion rates, and luminosity distances. The student will acquire and analyse such datasets, using parameterized models and Hornes maximum entropy fitting code MEMECHO.
Light travel time delays enable micro-arcsecond mapping of accretion disks and broad emission-line regions around the super-massive black holes in the nuclei of active galaxies. RoboNet provides the UK with unique datasets for measurement of black hole masses, accretion rates, and luminosity distances. The student will acquire and analyse such datasets, using parameterized models and Hornes maximum entropy fitting code MEMECHO.
Forming comet belts around nearby stars
Cameron, Prof Andrew - acc4@st-andrews.ac.uk
Greaves, Dr Jane - jsg5@st-andrews.ac.uk
Collisions of comets create dust belts that can be imaged at submillimetre wavelengths. The SCUBA-2 Legacy Survey starting early-2010 will explore what kinds of star have comets and if this is a signpost of extrasolar planets. We will help analyse the database of 500 stars to identify underlying stellar influences.
Greaves, Dr Jane - jsg5@st-andrews.ac.uk
Collisions of comets create dust belts that can be imaged at submillimetre wavelengths. The SCUBA-2 Legacy Survey starting early-2010 will explore what kinds of star have comets and if this is a signpost of extrasolar planets. We will help analyse the database of 500 stars to identify underlying stellar influences.
Ionisation in atmospheres across the star-planet mass boundary
Helling, Dr Christiane - ch80@st-andrews.ac.uk
The ionisation of the atmosphere depends on the local temperature which, in turn, depends on the effective temperature. We will study how the atmospheric electrification changes with decreasing effective temperature from the M-dwarfs into the Brown Dwarfs into the planetary mass regime.
See also LEAP PhD positions
The ionisation of the atmosphere depends on the local temperature which, in turn, depends on the effective temperature. We will study how the atmospheric electrification changes with decreasing effective temperature from the M-dwarfs into the Brown Dwarfs into the planetary mass regime.
See also LEAP PhD positions
Magnetic cycles in young stars
Jardine, Prof Moira - mmj@st-andrews.ac.uk
Wood, Dr Kenneth - kw25@st-andrews.ac.uk
In very young stars, material accreting from a surrounding disk is channelled by the star's magnetic field onto the stellar surface. We will use recently-acquired magnetic maps of these stars to model the impact of magnetic cycles on this accretion process.
Wood, Dr Kenneth - kw25@st-andrews.ac.uk
In very young stars, material accreting from a surrounding disk is channelled by the star's magnetic field onto the stellar surface. We will use recently-acquired magnetic maps of these stars to model the impact of magnetic cycles on this accretion process.
Mass Distribution of the Galaxy
Zhao, Dr Hongsheng - hz4@st-andrews.ac.uk
The mass distribution of the Galaxy is being / will be mapped out in great detail in the next decade with the numerous surveys of the Galaxy, including Segue, RAVE, GAIA, and completed ones like 2MASS, DENIS. A model for the potential and phase space of the galaxy is essential to bring various pieces of information together. The student will develop such models building on experience from existing models.
The mass distribution of the Galaxy is being / will be mapped out in great detail in the next decade with the numerous surveys of the Galaxy, including Segue, RAVE, GAIA, and completed ones like 2MASS, DENIS. A model for the potential and phase space of the galaxy is essential to bring various pieces of information together. The student will develop such models building on experience from existing models.
Microlens Survey for Cool Planets
Horne, Prof Keith - kdh1@st-andrews.ac.uk
Intensive monitoring of Galactic Bulge microlensing events is being used to discover cool planets in 1-5 AU orbits around the lens stars. Our PLANET/RoboNet team has just discovered a 5 earth-mass planet. In the next 4 years we aim to measure the abundance and mass function of cool planets to test theories of planet formation and migration. The student will work with our team to acquire and analyse observations, fit microlens models to characterize the planetary and other anomalies.
Intensive monitoring of Galactic Bulge microlensing events is being used to discover cool planets in 1-5 AU orbits around the lens stars. Our PLANET/RoboNet team has just discovered a 5 earth-mass planet. In the next 4 years we aim to measure the abundance and mass function of cool planets to test theories of planet formation and migration. The student will work with our team to acquire and analyse observations, fit microlens models to characterize the planetary and other anomalies.
Spindown of solar-type stars with age
Cameron, Prof Andrew - acc4@st-andrews.ac.uk
Greaves, Dr Jane - jsg5@st-andrews.ac.uk
Solar-type stars are born with a variety of spin rates. Magnetic braking theory predicts that the spread should narrow after a few times 10^8 y but observational surveys remain scanty. We will compile a complete survey of rotation periods in open clusters spanning the critical age range using photometry from the WASP project, and for field stars using publicly-released data from the CoRoT and Kepler space missions. The ultimate goal is to calibrate stellar spindown accurately enough for use in determining the ages of exoplanet host stars.
Greaves, Dr Jane - jsg5@st-andrews.ac.uk
Solar-type stars are born with a variety of spin rates. Magnetic braking theory predicts that the spread should narrow after a few times 10^8 y but observational surveys remain scanty. We will compile a complete survey of rotation periods in open clusters spanning the critical age range using photometry from the WASP project, and for field stars using publicly-released data from the CoRoT and Kepler space missions. The ultimate goal is to calibrate stellar spindown accurately enough for use in determining the ages of exoplanet host stars.
Star formation in dwarf galaxies
Bonnell, Prof Ian - iab1@st-andrews.ac.uk
This project is to develop the first models of resolved star formation on galactic scales. This will involve modelling a full galactic potential and how it drives the formation of molecular clouds and the onset of gravitational collapse and star formation. feedback from ionisation and supernova will be included to assess molecular cloud lifetimes and star formation efficiencies.
This project is to develop the first models of resolved star formation on galactic scales. This will involve modelling a full galactic potential and how it drives the formation of molecular clouds and the onset of gravitational collapse and star formation. feedback from ionisation and supernova will be included to assess molecular cloud lifetimes and star formation efficiencies.
Star-Planet Interaction
Jardine, Prof Moira - mmj@st-andrews.ac.uk
Tau Boo is the only star for which we have been able to track the full cyclic reversal of the stellar magnetic field. This system is also well-known, however, because it hosts a Hot Jupiter that is so close to the star that it may lie within the stellar corona. What is the nature of the interaction between the star and planet in this case and is it related to the puzzling nature of the very short magnetic cycle? This project will investigate tau Boo and other similar star-planet systems.
Tau Boo is the only star for which we have been able to track the full cyclic reversal of the stellar magnetic field. This system is also well-known, however, because it hosts a Hot Jupiter that is so close to the star that it may lie within the stellar corona. What is the nature of the interaction between the star and planet in this case and is it related to the puzzling nature of the very short magnetic cycle? This project will investigate tau Boo and other similar star-planet systems.
Structure and evolution of protoplanetary disks.
Greaves, Dr Jane - jsg5@st-andrews.ac.uk
Wood, Dr Kenneth - kw25@st-andrews.ac.uk
Understanding the structure, composition, and dynamics of protoplanetary disks are crucial for planet formation theories. This project will combine dynamical models of disks with 3D radiation transfer and new multiwavelength imaging and spectroscopy to study dust growth and settling, disk-planet interactions, and signatures of massive, self-gravitating disks.
Wood, Dr Kenneth - kw25@st-andrews.ac.uk
Understanding the structure, composition, and dynamics of protoplanetary disks are crucial for planet formation theories. This project will combine dynamical models of disks with 3D radiation transfer and new multiwavelength imaging and spectroscopy to study dust growth and settling, disk-planet interactions, and signatures of massive, self-gravitating disks.
Studying planet populations by means of gravitational microlensing
Dominik, Dr Martin - md35@st-andrews.ac.uk
With more than 400 planets orbiting stars other than the Sun known (as of March 2010), observing campaigns now need to evolve from the pure detection of planets to studies that allow to infer the statistical properties of the underlying populations that are being probed. Only by comparing a wide planet census with model predictions of planet formation and evolution, will we be able to understand the origin (and future!) of habitable planets, and Earth in particular. Due to their probabilistic nature, gravitational microlensing experiments are particularly challenging, but they are suited to provide insight that remains hidden to any other known technique, with a sensitivity reaching even below Earth mass, and the possibility to spot signatures of planets orbiting stars in other galaxies. The realisation of a fully-deterministic observing strategy is a necessary prerequisite for measuring planet abundances. Over the recent years, we have been working on the development of the world-leading technology for implementing an automated microlensing campaign that is carried out by means of our RoboNet-II and MiNDSTEp telescope networks, and informed about the targets to be observed by the publically-accessible ARTEMiS system. Two specific topics currently call for special attention:
1) Further development of ARTEMiS is required to provide a target recommendation for a non-proprietary heterogeneous network of telescopes according to a user-defined strategy, the currently available data, the individual telescope capabilities, and the observability. Gravitational microlensing is a showcase application for modern telescope scheduling, and by its strong demands on flexibility and reaction time leads to pioneering concepts that can be of far more general use. Moreover, ARTEMiS not only provides tools to astronomers, but also brings forefront science to the general public.
2) Imperfections in the data reduction lead to various types of spurious signals, which either need to be properly identified and separated from real variations, or to be treated statistically as a form of background noise. The low-mass sensitivity limit of our campaigns crucially depends on how well we understand this. Moreover, a proper understanding of false positives will make a difference on the efficiency of our monitoring programme by allowing more appropriate decisions based on real-time data.
Further Links:
MiNDSTEp www.mindstep-science.org
ARTEMiS www.artemis-uk.org
With more than 400 planets orbiting stars other than the Sun known (as of March 2010), observing campaigns now need to evolve from the pure detection of planets to studies that allow to infer the statistical properties of the underlying populations that are being probed. Only by comparing a wide planet census with model predictions of planet formation and evolution, will we be able to understand the origin (and future!) of habitable planets, and Earth in particular. Due to their probabilistic nature, gravitational microlensing experiments are particularly challenging, but they are suited to provide insight that remains hidden to any other known technique, with a sensitivity reaching even below Earth mass, and the possibility to spot signatures of planets orbiting stars in other galaxies. The realisation of a fully-deterministic observing strategy is a necessary prerequisite for measuring planet abundances. Over the recent years, we have been working on the development of the world-leading technology for implementing an automated microlensing campaign that is carried out by means of our RoboNet-II and MiNDSTEp telescope networks, and informed about the targets to be observed by the publically-accessible ARTEMiS system. Two specific topics currently call for special attention:
1) Further development of ARTEMiS is required to provide a target recommendation for a non-proprietary heterogeneous network of telescopes according to a user-defined strategy, the currently available data, the individual telescope capabilities, and the observability. Gravitational microlensing is a showcase application for modern telescope scheduling, and by its strong demands on flexibility and reaction time leads to pioneering concepts that can be of far more general use. Moreover, ARTEMiS not only provides tools to astronomers, but also brings forefront science to the general public.
2) Imperfections in the data reduction lead to various types of spurious signals, which either need to be properly identified and separated from real variations, or to be treated statistically as a form of background noise. The low-mass sensitivity limit of our campaigns crucially depends on how well we understand this. Moreover, a proper understanding of false positives will make a difference on the efficiency of our monitoring programme by allowing more appropriate decisions based on real-time data.
Further Links:
MiNDSTEp www.mindstep-science.org
ARTEMiS www.artemis-uk.org
The link between planetary atmosphere and planetary magnetic field
Helling, Dr Christiane - ch80@st-andrews.ac.uk
We will study how a brown dwarf and a planetary atmosphere interacts with a planetary magnetic field and how this might be observable.
See also LEAP PhD positions
We will study how a brown dwarf and a planetary atmosphere interacts with a planetary magnetic field and how this might be observable.
See also LEAP PhD positions
The role of gas-rich major mergers in building elliptical galaxies
Wild, Dr Vivienne - vw8@st-andrews.ac.uk
The dominant physical processes responsible for the growth and evolution of galaxies over the history of the Universe are not well understood. Popular theories suggest gas-rich galaxy mergers are key in triggering star formation, altering the morphology of the galaxies, and causing supermassive black hole growth, however direct observational evidence remains scarce.
The aim of this project is to determine the true role of mergers in defining the galaxy population around us today. This will involve the analysis of the soon-to-be-completed spectroscopic and multi wavelength galaxy survey GAMA, and the concurrent analysis of hydrodynamic models of galaxy mergers with which to compare the observational data.
The project may involve extended stays in Finland or Germany to work with colleagues on the development of the models and image analysis techniques, or Australia to work on analysing results from the GAMA survey. At the end of the PhD, the student will be well placed to apply the analysis techniques that they have developed to the most important high-redshift datasets of the next decade with the launch of JWST in ~2016-2018.
Links:
The GAMA survey: http://www.gama-survey.org/
The James Web Space Telescope http://www.jwst.nasa.gov/
This project may be funded by the European Union and St Andrews University and we therefore welcome applications from all nationalities.
Note that Vivienne will be moving to St Andrews as a lecturer from January 2012. Please see her website for more information about her research: http://www.roe.ac.uk/~vw/
The dominant physical processes responsible for the growth and evolution of galaxies over the history of the Universe are not well understood. Popular theories suggest gas-rich galaxy mergers are key in triggering star formation, altering the morphology of the galaxies, and causing supermassive black hole growth, however direct observational evidence remains scarce.
The aim of this project is to determine the true role of mergers in defining the galaxy population around us today. This will involve the analysis of the soon-to-be-completed spectroscopic and multi wavelength galaxy survey GAMA, and the concurrent analysis of hydrodynamic models of galaxy mergers with which to compare the observational data.
The project may involve extended stays in Finland or Germany to work with colleagues on the development of the models and image analysis techniques, or Australia to work on analysing results from the GAMA survey. At the end of the PhD, the student will be well placed to apply the analysis techniques that they have developed to the most important high-redshift datasets of the next decade with the launch of JWST in ~2016-2018.
Links:
The GAMA survey: http://www.gama-survey.org/
The James Web Space Telescope http://www.jwst.nasa.gov/
This project may be funded by the European Union and St Andrews University and we therefore welcome applications from all nationalities.
Note that Vivienne will be moving to St Andrews as a lecturer from January 2012. Please see her website for more information about her research: http://www.roe.ac.uk/~vw/
Triggering of star formation
Bonnell, Prof Ian - iab1@st-andrews.ac.uk
There are several outstanding issues in current models of star formation. One of these is the role of feedback from young stars in producing subsequent generations of young stars. Triggering of star formation through supernova events is likely to be the dominant mechanism. Numerical simulations of SNII impacting on molecular clouds and the triggering of star formation will be used to develop physical models, and ultimately observational predictions and tests of the process.
There are several outstanding issues in current models of star formation. One of these is the role of feedback from young stars in producing subsequent generations of young stars. Triggering of star formation through supernova events is likely to be the dominant mechanism. Numerical simulations of SNII impacting on molecular clouds and the triggering of star formation will be used to develop physical models, and ultimately observational predictions and tests of the process.
Wide-angle search for transiting planets
Cameron, Prof Andrew - acc4@st-andrews.ac.uk
The WASP project (http://www.superwasp.org) is a consortium comprising 6 UK universities and 3 overseas observatories. We use two arrays of wide-field camera lenses backed by large-format CCDs to perform high-precision photometry of millions of stars each night, looking for the 1% dips in light that betray gas-giant planets whose orbital planes are close enough to the line of sight that they transit their host stars. Our current catch stands at 70 planets confirmed by radial-velocity follow-up. There is an opening at St Andrews for a PhD student to work on a combination of project infrastructure and science exploitation. Possible components of a PhD project include:
- Improving the quality of the SuperWASP photometry using image-subtraction and profile-fitting methods;
- Improving the transit detection and pre-selection criteria to eliminate astrophysical and other false positives;
- Measuring stellar spin rates and spin-orbit misalignments using time-resolved spectroscopy during transits;
- Determining the ages of transiting planet systems from the spin rates of the host stars;
- Modelling the tidal spin-orbit interaction between the closest-orbiting hot Jupiters and their host stars;
- Using high-resolution time-series transit spectroscopy to confirm the presence of planets around early-type stars;
- Reconciling the planet catch with models of the galactic planet population and observational detection thresholds;
- Modelling the infrared spectra of hot-Jupiter atmospheres for comparison with Spitzer/IRAC secondary-eclipse photometry;
- Building or using simple planetary structural models as a tool to aid understanding of the mass-radius relation for transiting hot Jupiters as a function of age, core mass, envelope metallicity, stellar irradiation etc.
The WASP project (http://www.superwasp.org) is a consortium comprising 6 UK universities and 3 overseas observatories. We use two arrays of wide-field camera lenses backed by large-format CCDs to perform high-precision photometry of millions of stars each night, looking for the 1% dips in light that betray gas-giant planets whose orbital planes are close enough to the line of sight that they transit their host stars. Our current catch stands at 70 planets confirmed by radial-velocity follow-up. There is an opening at St Andrews for a PhD student to work on a combination of project infrastructure and science exploitation. Possible components of a PhD project include:
- Improving the quality of the SuperWASP photometry using image-subtraction and profile-fitting methods;
- Improving the transit detection and pre-selection criteria to eliminate astrophysical and other false positives;
- Measuring stellar spin rates and spin-orbit misalignments using time-resolved spectroscopy during transits;
- Determining the ages of transiting planet systems from the spin rates of the host stars;
- Modelling the tidal spin-orbit interaction between the closest-orbiting hot Jupiters and their host stars;
- Using high-resolution time-series transit spectroscopy to confirm the presence of planets around early-type stars;
- Reconciling the planet catch with models of the galactic planet population and observational detection thresholds;
- Modelling the infrared spectra of hot-Jupiter atmospheres for comparison with Spitzer/IRAC secondary-eclipse photometry;
- Building or using simple planetary structural models as a tool to aid understanding of the mass-radius relation for transiting hot Jupiters as a function of age, core mass, envelope metallicity, stellar irradiation etc.
Condensed Matter
Direct measurement of the entropic landscape in quantum critical systems
Grigera, Dr Santiago - sag2@st-andrews.ac.uk
Mackenzie, Prof Andy - apm9@st-andrews.ac.uk
Rost, Dr Andreas - ar35@st-andrews.ac.uk
Quantum criticality is one of the most intriguing fields of research in modern condensed matter physics. A quantum critical point is a continuous phase transition for which the phase change is driven by quantum rather than thermal fluctuations, and the approach to quantum criticality has proven to be an effective ‘breeding ground’ for the formation of novel quantum order [1]. In a recent breakthrough during the PhD work of Andreas Rost, we have shown that precise measurement of the magneto-caloric effect can be used to deduce the full magnetic field and temperature dependence of the entropy of a system on the verge of quantum criticality, making far fewer assumptions than are necessary if deducing it purely from the specific heat. The entropy is arguably the most fundamental of all thermodynamic potentials, so this gives us access to a class of information not previously attainable experimentally. So far, we have only studied Sr3Ru2O7 using our new technique. This project will involve work on other known quantum critical systems, and probably also the extension to entirely new ones.
[1] A.P. Mackenzie & S.A. Grigera, Science 309, 1330 (2005) and references therein.
Mackenzie, Prof Andy - apm9@st-andrews.ac.uk
Rost, Dr Andreas - ar35@st-andrews.ac.uk
Quantum criticality is one of the most intriguing fields of research in modern condensed matter physics. A quantum critical point is a continuous phase transition for which the phase change is driven by quantum rather than thermal fluctuations, and the approach to quantum criticality has proven to be an effective ‘breeding ground’ for the formation of novel quantum order [1]. In a recent breakthrough during the PhD work of Andreas Rost, we have shown that precise measurement of the magneto-caloric effect can be used to deduce the full magnetic field and temperature dependence of the entropy of a system on the verge of quantum criticality, making far fewer assumptions than are necessary if deducing it purely from the specific heat. The entropy is arguably the most fundamental of all thermodynamic potentials, so this gives us access to a class of information not previously attainable experimentally. So far, we have only studied Sr3Ru2O7 using our new technique. This project will involve work on other known quantum critical systems, and probably also the extension to entirely new ones.
[1] A.P. Mackenzie & S.A. Grigera, Science 309, 1330 (2005) and references therein.
Electrical Transport and Calorimetry in Sr3Ru2O7 in Vector Magnetic Fields
Grigera, Dr Santiago - sag2@st-andrews.ac.uk
Mackenzie, Prof Andy - apm9@st-andrews.ac.uk
The material at the heart of this project, Sr3Ru2O7, is one of the most fascinating in condensed matter physics. Over a decade of study, our collaboration has succeeded in growing the world’s purest single crystals of it, and discovering that in the very best crystals, a new quantum phase forms at high magnetic fields [1]. This phase appears to have the characteristics of an electronic nematic liquid crystal of the sort predicted in the late 1990s [2], with the properties making a transition from four-fold to two-fold symmetric over a narrow range of applied field. The observations to date raise a number of intriguing questions about the behaviour of such systems, which can only be answered by study in rotating, or ‘vector’ magnetic fields. In a major project funded by the UK’s Engineering and Physical Sciences Research Council, we have commissioned the design and construction of the world’s largest three-axis vector magnet, which is scheduled for delivery in early summer 2009. This project will involve using the unique new capability to perform both transport and thermodynamic measurements as the field angle is rotated relative to the crystal axes of the sample.
[1] R.A. Borzi, S.A. Grigera, J. Farrell, R.S. Perry, S. Lister, S.L. Lee, D.A. Tennant, Y. Maeno & A.P. Mackenzie, Science 315, 214 (2007).
[2] S. A. Kivelson, E. Fradkin, V. J. Emery, Nature 393, 550 (1998).
Mackenzie, Prof Andy - apm9@st-andrews.ac.uk
The material at the heart of this project, Sr3Ru2O7, is one of the most fascinating in condensed matter physics. Over a decade of study, our collaboration has succeeded in growing the world’s purest single crystals of it, and discovering that in the very best crystals, a new quantum phase forms at high magnetic fields [1]. This phase appears to have the characteristics of an electronic nematic liquid crystal of the sort predicted in the late 1990s [2], with the properties making a transition from four-fold to two-fold symmetric over a narrow range of applied field. The observations to date raise a number of intriguing questions about the behaviour of such systems, which can only be answered by study in rotating, or ‘vector’ magnetic fields. In a major project funded by the UK’s Engineering and Physical Sciences Research Council, we have commissioned the design and construction of the world’s largest three-axis vector magnet, which is scheduled for delivery in early summer 2009. This project will involve using the unique new capability to perform both transport and thermodynamic measurements as the field angle is rotated relative to the crystal axes of the sample.
[1] R.A. Borzi, S.A. Grigera, J. Farrell, R.S. Perry, S. Lister, S.L. Lee, D.A. Tennant, Y. Maeno & A.P. Mackenzie, Science 315, 214 (2007).
[2] S. A. Kivelson, E. Fradkin, V. J. Emery, Nature 393, 550 (1998).
Exciton Diffusion in Organic Semiconductors
Samuel, Prof Ifor - idws@st-andrews.ac.uk
The discovery of semiconducting properties in organic materials has opened major new directions in semiconductor physics. Organic semiconductors combine the simple fabrication and tuning of properties that is typical of plastics with novel optoelectronic properties useful for devices such as light-emitting diodes and solar cells. The low-dimensional nature of these materials means that excitons (electron-hole pairs) are strongly bound even at room temperature and play a very important role in their physics. Whilst charge transport has been widely studied, exciton transport has been largely overlooked. We have now developed techniques based on time-resolved spectroscopy that allow the measurement of exciton diffusion. We now wish to apply them to understand the physics of exciton diffusion and the factors controlling it. A breakthrough in this field could in turn lead to a breakthrough in the efficiency of organic solar cells.
The discovery of semiconducting properties in organic materials has opened major new directions in semiconductor physics. Organic semiconductors combine the simple fabrication and tuning of properties that is typical of plastics with novel optoelectronic properties useful for devices such as light-emitting diodes and solar cells. The low-dimensional nature of these materials means that excitons (electron-hole pairs) are strongly bound even at room temperature and play a very important role in their physics. Whilst charge transport has been widely studied, exciton transport has been largely overlooked. We have now developed techniques based on time-resolved spectroscopy that allow the measurement of exciton diffusion. We now wish to apply them to understand the physics of exciton diffusion and the factors controlling it. A breakthrough in this field could in turn lead to a breakthrough in the efficiency of organic solar cells.
Exotic Kondo effects in tunable nanostructures
Hooley, Dr Chris - cah19@st-andrews.ac.uk
When a magnetic impurity (such as iron) is placed in a good metal, it causes anomalously strong scattering of the conduction electrons below a certain characteristic temperature. This effect is called the Kondo effect, and the associated temperature is therefore called the Kondo temperature. We now understand that what the magnetic impurity is trying to do is to bind the conduction electrons into a spin-singlet, and at sufficiently low temperatures, this is achieved. In 1998, the effect was observed for the first time in nanophysical systems, with a quantum dot playing the role of the magnetic impurity, and the two electrical leads playing the role of the conduction sea. Quantum dot systems are, however, much more tunable than the metals and impurities offered to us by chemistry: even the dimensionality of the leads can in principle be altered. This is an exciting prospect, since we know that in one dimension the interacting electron system adopts an unusual strongly correlated state called a Luttinger liquid, and that the theory of the Kondo effect with Luttinger liquid leads is quite different to that in the normal metal case. This theoretical project aims to address the following questions:
- Can the Luttinger-liquid Kondo effect be realised in quantum dot systems?
- How do its properties relate to those of the soft-gap Anderson model?
- What is its behaviour at bias voltages well above the Kondo scale?
- Does it have a critical point, and if so, can this be characterised?
Established relations with several experimental groups active in the field (e.g. the Grayson group at the Walter Schottky Institute, the Marcus group at Harvard, and the Kouwenhoven group at Delft) are expected to provide fruitful and up-to-date experimental information. The majority of the work will consist of pen-and-paper calculations, perhaps supplemented by some computational analysis.
When a magnetic impurity (such as iron) is placed in a good metal, it causes anomalously strong scattering of the conduction electrons below a certain characteristic temperature. This effect is called the Kondo effect, and the associated temperature is therefore called the Kondo temperature. We now understand that what the magnetic impurity is trying to do is to bind the conduction electrons into a spin-singlet, and at sufficiently low temperatures, this is achieved. In 1998, the effect was observed for the first time in nanophysical systems, with a quantum dot playing the role of the magnetic impurity, and the two electrical leads playing the role of the conduction sea. Quantum dot systems are, however, much more tunable than the metals and impurities offered to us by chemistry: even the dimensionality of the leads can in principle be altered. This is an exciting prospect, since we know that in one dimension the interacting electron system adopts an unusual strongly correlated state called a Luttinger liquid, and that the theory of the Kondo effect with Luttinger liquid leads is quite different to that in the normal metal case. This theoretical project aims to address the following questions:
- Can the Luttinger-liquid Kondo effect be realised in quantum dot systems?
- How do its properties relate to those of the soft-gap Anderson model?
- What is its behaviour at bias voltages well above the Kondo scale?
- Does it have a critical point, and if so, can this be characterised?
Established relations with several experimental groups active in the field (e.g. the Grayson group at the Walter Schottky Institute, the Marcus group at Harvard, and the Kouwenhoven group at Delft) are expected to provide fruitful and up-to-date experimental information. The majority of the work will consist of pen-and-paper calculations, perhaps supplemented by some computational analysis.
Experimental and Theoretical Investigation of Spatially Modulated Magnetic Phases Near to Quantum Criticality
Huxley, Prof Andrew - ah311@st-andrews.ac.uk
The possibility of magnetic spin-crystals formed by the superposition of helical spin modulations with different wave-vectors has been a subject of much recent experimental and theoretical work. Signatures of phases with this property have been found in an array of materials including MnSi and Sr3Ru2O7. On the theoretical side, there are several ways in which such states might form. These include the formation of spiral modulation due to a Dzyalosinskii-Moriya spin-orbit interaction in itinerant magnets, residual, small-wavevector nesting due to the electron dispersion in a lattice [1,2] and from competing interactions that can give rise to a series of transitions forming a Devil's Staircase [3]. Perhaps the most intriguing suggestion - and one that has most captured the imagination of condensed matter theorists of late - is that an itinerant system on the brink of a quantum phase transition might possess an intrinsic instability to the formation of modulated magnetic phases [4]. In any particular material, one or more of these effects may operate with the possibility of a complicated interplay between them.
This project aims to investigate the phenomenon of spatially modulated magnetism from both an experimental and theoretical perspective. We will use techniques of quantum many-body physics and field theory to investigate the possibility of spatially modulated magnetism in real systems. These investigations will be carried out in concert with neutron scattering experiments to provide inspiration for and validate this theory. The experimental part will include growing the crystals for these experiments as well as performing the measurements. We anticipate that a student will spend approximately 2/3 of their time on theory and 1/3 on experimental work, working both in Edinburgh and St Andrews as well as at international facilities.
[1] A. M. Berridge, A. G. Green, S. A. Grigera and B. D. Simons "A Magnetic Analogue of the of the FFLO state: Inhomogeneous Instabilities Near to Tricritical Points" Physical Review Letters 102, 149903 (2009).
[2] G. J. Conduit, A. G. Green, and B. D. Simons, "Inhomogeneous phase formation on the border of itinerant ferromagnetism" Physical Review Letters 103, 207201 (2009) [spotlighted in Physics 2, 93 (2009)]
[3] P. Bak & J. von Boehm, "Ising model with solitons, phasons, and 'the devil's staircase'", Phys Rev B 21 5297 (1980)
[4] J. Rech C.Pépin, V.Chubukov, "Quantum critical behaviour in intinerant electron systems: Eliashberg theory and instability of a ferromagentic quantum critical point" Phys Rev B 74 195126 (2006)
The possibility of magnetic spin-crystals formed by the superposition of helical spin modulations with different wave-vectors has been a subject of much recent experimental and theoretical work. Signatures of phases with this property have been found in an array of materials including MnSi and Sr3Ru2O7. On the theoretical side, there are several ways in which such states might form. These include the formation of spiral modulation due to a Dzyalosinskii-Moriya spin-orbit interaction in itinerant magnets, residual, small-wavevector nesting due to the electron dispersion in a lattice [1,2] and from competing interactions that can give rise to a series of transitions forming a Devil's Staircase [3]. Perhaps the most intriguing suggestion - and one that has most captured the imagination of condensed matter theorists of late - is that an itinerant system on the brink of a quantum phase transition might possess an intrinsic instability to the formation of modulated magnetic phases [4]. In any particular material, one or more of these effects may operate with the possibility of a complicated interplay between them.
This project aims to investigate the phenomenon of spatially modulated magnetism from both an experimental and theoretical perspective. We will use techniques of quantum many-body physics and field theory to investigate the possibility of spatially modulated magnetism in real systems. These investigations will be carried out in concert with neutron scattering experiments to provide inspiration for and validate this theory. The experimental part will include growing the crystals for these experiments as well as performing the measurements. We anticipate that a student will spend approximately 2/3 of their time on theory and 1/3 on experimental work, working both in Edinburgh and St Andrews as well as at international facilities.
[1] A. M. Berridge, A. G. Green, S. A. Grigera and B. D. Simons "A Magnetic Analogue of the of the FFLO state: Inhomogeneous Instabilities Near to Tricritical Points" Physical Review Letters 102, 149903 (2009).
[2] G. J. Conduit, A. G. Green, and B. D. Simons, "Inhomogeneous phase formation on the border of itinerant ferromagnetism" Physical Review Letters 103, 207201 (2009) [spotlighted in Physics 2, 93 (2009)]
[3] P. Bak & J. von Boehm, "Ising model with solitons, phasons, and 'the devil's staircase'", Phys Rev B 21 5297 (1980)
[4] J. Rech C.Pépin, V.Chubukov, "Quantum critical behaviour in intinerant electron systems: Eliashberg theory and instability of a ferromagentic quantum critical point" Phys Rev B 74 195126 (2006)
Integrated Magnetic Resonance Doctoral Training Centre
Smith, Dr Graham - gms@st-andrews.ac.uk
The new EPSRC Doctoral Training Centre in Integrated Magnetic Resonance is a collaboration between 6 of the UK's leading Universities in Advanced Magnetic Resonance Instrumentation and Techniques and includes St. Andrews, Dundee, Aberdeen, Warwick, Nottingham and Southampton.
The aim is to provide a coherent training program for doctoral students whilst working on new research topics in instrumentation and methodology, associated with Magnetic Resonance Imaging, Electron Magnetic Resonance, Nuclear Magnetic Resonance and Dynamic Nuclear Polarisation (which collectively represent £multi-Billion annual markets). Training is delivered from all centres, through residential workshops and over the Access Grid, primarily in the first two years of study.
Funded 4 year PhDs include fees and maintenance of £14000 (tax free) per annum as well as an enhanced travel budget. All PhDs will have internal and external mentors from other centres.
At St Andrews, PhD projects are available on themes associated with major advances in Electron Magnetic Resonance and Dynamic Nuclear Polarisation and are likely to involve collaborations with other centres and other interdisciplinary groups.
PhD topics are likely to involve a combination of instrumental, methodological and computational techniques that would normally be associated with Basic Technology programs.
Representative PhDs from all 6 centres are listed on www.imr-cdt.ac.uk, but other PhD topics may be available on request.
For PhDs at St Andrews, applications can be made directly to St Andrews or via Warwick where the DTC program is administered.
The new EPSRC Doctoral Training Centre in Integrated Magnetic Resonance is a collaboration between 6 of the UK's leading Universities in Advanced Magnetic Resonance Instrumentation and Techniques and includes St. Andrews, Dundee, Aberdeen, Warwick, Nottingham and Southampton.
The aim is to provide a coherent training program for doctoral students whilst working on new research topics in instrumentation and methodology, associated with Magnetic Resonance Imaging, Electron Magnetic Resonance, Nuclear Magnetic Resonance and Dynamic Nuclear Polarisation (which collectively represent £multi-Billion annual markets). Training is delivered from all centres, through residential workshops and over the Access Grid, primarily in the first two years of study.
Funded 4 year PhDs include fees and maintenance of £14000 (tax free) per annum as well as an enhanced travel budget. All PhDs will have internal and external mentors from other centres.
At St Andrews, PhD projects are available on themes associated with major advances in Electron Magnetic Resonance and Dynamic Nuclear Polarisation and are likely to involve collaborations with other centres and other interdisciplinary groups.
PhD topics are likely to involve a combination of instrumental, methodological and computational techniques that would normally be associated with Basic Technology programs.
Representative PhDs from all 6 centres are listed on www.imr-cdt.ac.uk, but other PhD topics may be available on request.
For PhDs at St Andrews, applications can be made directly to St Andrews or via Warwick where the DTC program is administered.
Investigating the interplay of magnetism and superconductivity in thin film devices using advanced neutron, muon and synchrotron techniques
Lee, Prof Steve - sl10@st-andrews.ac.uk
Nanomagnetic devices are present in many high technology systems, a classical example being hard disk drives, where they find use in both the recording media and the magnetoresistive read heads. There is currently an enormous effort in the area of ‘spintronics’, where idealized thin film structures are fabricated to create spin-polarised currents that could find application in a new generation of electronic devices. These devices, such as ‘spin valves’, typically combine juxtaposed layers of magnetic metals and normal metals each of typical thickness a few 10’s of nanometers.
In this project we extend the notion of spintronic devices to include magnetic and superconducting elements. Superconductivity and magnetism are frequently mutually exclusive and in instances where they do coexist in close proximity this usually implies some exotic ground state for the system. In superconducting spintronic devices one could envisage the magnetic switch controlling the superconducting wavefunction (amplitude and possibly phase) that could used to exploit quantum properties in future electronics and computing. We have also recently demonstrated that the superconducting state can also influence the magnetic state of the system.
We are using traditional neutron techniques combined with a completely novel and unique technique, the low energy muon (LEM) facility at the Paul Scherrer Institute (PSI), Switzerland, to study the delicate interplay of magnetism and superconductivity in superconducting spin-valve and related systems. We have already been able to demonstrate the coexistence of superconductivity and a spin density wave using this approach, which is attracting attention from theorists working in this area.
The PhD position offers a great opportunity for a highly motivated student to receive outstanding training in advanced techniques at some of the world’s leading central facilities in France, Switzlerland, Germany and the UK. The work is carried out in collaboration with the world renowned group in Leiden headed by Professor Jan Aarts.
The work is currently supported under an EU facilities user programme at PSI and via the EPSRC direct access programme at the Institut Laue Langevin in Grenoble, France and at ISIS, UK. Further support is soon to be sought from the EPSRC to enlarge the scope of the programme.
Please make any informal enquiries to Professor Steve Lee, sl10@st-and.ac.uk.
Nanomagnetic devices are present in many high technology systems, a classical example being hard disk drives, where they find use in both the recording media and the magnetoresistive read heads. There is currently an enormous effort in the area of ‘spintronics’, where idealized thin film structures are fabricated to create spin-polarised currents that could find application in a new generation of electronic devices. These devices, such as ‘spin valves’, typically combine juxtaposed layers of magnetic metals and normal metals each of typical thickness a few 10’s of nanometers.
In this project we extend the notion of spintronic devices to include magnetic and superconducting elements. Superconductivity and magnetism are frequently mutually exclusive and in instances where they do coexist in close proximity this usually implies some exotic ground state for the system. In superconducting spintronic devices one could envisage the magnetic switch controlling the superconducting wavefunction (amplitude and possibly phase) that could used to exploit quantum properties in future electronics and computing. We have also recently demonstrated that the superconducting state can also influence the magnetic state of the system.
We are using traditional neutron techniques combined with a completely novel and unique technique, the low energy muon (LEM) facility at the Paul Scherrer Institute (PSI), Switzerland, to study the delicate interplay of magnetism and superconductivity in superconducting spin-valve and related systems. We have already been able to demonstrate the coexistence of superconductivity and a spin density wave using this approach, which is attracting attention from theorists working in this area.
The PhD position offers a great opportunity for a highly motivated student to receive outstanding training in advanced techniques at some of the world’s leading central facilities in France, Switzlerland, Germany and the UK. The work is carried out in collaboration with the world renowned group in Leiden headed by Professor Jan Aarts.
The work is currently supported under an EU facilities user programme at PSI and via the EPSRC direct access programme at the Institut Laue Langevin in Grenoble, France and at ISIS, UK. Further support is soon to be sought from the EPSRC to enlarge the scope of the programme.
Please make any informal enquiries to Professor Steve Lee, sl10@st-and.ac.uk.
Laser based ARPES from ultra-pure correlated electron systems
Baumberger, Dr Felix - fb40@st-andrews.ac.uk
Tamai, Dr Anna - at71@st-andrews.ac.uk
The goal of this project is to investigate the electronic structure of strongly correlated metallic oxides with unprecedented accuracy. To this end you will use a novel highly intense UV laser source to perform ultrahigh resolution angle resolved photoemission (ARPES) studies on ruthenates and related materials.
ARPES is a uniquely powerful spectroscopic technique for electronic structure measurements. However, reaching the minute energy and temperature scales of some of the most intriguing phenomena in condensed matter systems remains a challenge. In this project you will commission a new laser based UV light source with significantly higher brilliance than today's best synchrotron beamlines and explore the potential of this instrument for very high resolution photoelectron spectroscopy using our existing state-of-the-art electron spectrometer.
For further information please contact Felix Baumberger
Tamai, Dr Anna - at71@st-andrews.ac.uk
The goal of this project is to investigate the electronic structure of strongly correlated metallic oxides with unprecedented accuracy. To this end you will use a novel highly intense UV laser source to perform ultrahigh resolution angle resolved photoemission (ARPES) studies on ruthenates and related materials.
ARPES is a uniquely powerful spectroscopic technique for electronic structure measurements. However, reaching the minute energy and temperature scales of some of the most intriguing phenomena in condensed matter systems remains a challenge. In this project you will commission a new laser based UV light source with significantly higher brilliance than today's best synchrotron beamlines and explore the potential of this instrument for very high resolution photoelectron spectroscopy using our existing state-of-the-art electron spectrometer.
For further information please contact Felix Baumberger
Magnetic measurements to probe unconventional superconductors
Huxley, Prof Andrew - ah311@st-andrews.ac.uk
Yelland, Dr Ed - eay1@st-andrews.ac.uk
Magnetism and superconductivity are intimately connected in many so-called heavy fermion metals. A particularly dramatic case is URhGe, where two distinct superconducting regions exist – one coexisting with ferromagnetism, and the other at extremely strong applied magnetic fields that are sufficient to destroy conventional forms of superconductivity. This project will involve developing sensitive magnetic measurement apparatus that will operate at extremes of low temperature, high magnetic field and high pressure, and apply them to study URhGe and other related materials. The aims are both to gain a deeper understanding of how magnetic pairing may lead to superconductivity and to drive the search for new superconducting materials. The project could be based in either St Andrews or Edinburgh.
The project is an integral part of a major research effort to study quantum criticality and unusual quantum ordered phases using a variety of magnetic, electrical and thermal measurement techniques. The apparatus in St Andrews includes a state-of-the-art dilution refrigerator (commissioned December 2007) with a base temperature 10 millikelvin and equipped with a 17 tesla magnet, that will allow coverage of a wide region of experimental parameter space, including applied pressures up to 100 kbar.
The focus for the project is on magnetic measurements including torque magnetometry, field gradient magnetometry and a.c. susceptibility. By combining torque and field-gradient results, the vector magnetic moment can be determined as a function of magnetic field and its angle to the crystallographic axes. This will allow a complete phenomenological (Ginzburg-Landau) description of the magnetism close to the superconducting phase to be constructed, and will provide detailed information about the nature of the magnetic interactions that are important for superconductivity. Another important component of the work will be to use quantum oscillations in various magnetic quantities to study the Fermi surface and how these change approaching and crossing quantum phase transitions.
Yelland, Dr Ed - eay1@st-andrews.ac.uk
Magnetism and superconductivity are intimately connected in many so-called heavy fermion metals. A particularly dramatic case is URhGe, where two distinct superconducting regions exist – one coexisting with ferromagnetism, and the other at extremely strong applied magnetic fields that are sufficient to destroy conventional forms of superconductivity. This project will involve developing sensitive magnetic measurement apparatus that will operate at extremes of low temperature, high magnetic field and high pressure, and apply them to study URhGe and other related materials. The aims are both to gain a deeper understanding of how magnetic pairing may lead to superconductivity and to drive the search for new superconducting materials. The project could be based in either St Andrews or Edinburgh.
The project is an integral part of a major research effort to study quantum criticality and unusual quantum ordered phases using a variety of magnetic, electrical and thermal measurement techniques. The apparatus in St Andrews includes a state-of-the-art dilution refrigerator (commissioned December 2007) with a base temperature 10 millikelvin and equipped with a 17 tesla magnet, that will allow coverage of a wide region of experimental parameter space, including applied pressures up to 100 kbar.
The focus for the project is on magnetic measurements including torque magnetometry, field gradient magnetometry and a.c. susceptibility. By combining torque and field-gradient results, the vector magnetic moment can be determined as a function of magnetic field and its angle to the crystallographic axes. This will allow a complete phenomenological (Ginzburg-Landau) description of the magnetism close to the superconducting phase to be constructed, and will provide detailed information about the nature of the magnetic interactions that are important for superconductivity. Another important component of the work will be to use quantum oscillations in various magnetic quantities to study the Fermi surface and how these change approaching and crossing quantum phase transitions.
Mesoscopic unconventional superconductors and Fermi liquids
Mackenzie, Prof Andy - apm9@st-andrews.ac.uk
This project is offer in conjunction with Prof. Amir Yacoby at Harvard.
In this project, we aim to bridge the gap between two fields in which huge progress has been made over the past twenty years. In mesoscopic physics, the aim is to work with samples that are specially fabricated so that their physical size becomes comparable with one or more of the fundamental length scales of the underlying physics. In a metal this might be the mean free path, and in a superconductor it might be the coherence length or the penetration depth. So far, the vast majority of research into mesoscopic physics has been performed on traditional materials in which the electron-electron interactions are relatively weak. In parallel with these developments, equally rapid progress has been made on research into new materials with very strong electron-electron interactions, which lead to high quasiparticle masses and an exciting variety of metallic, superconducting and magnetic ground states. For technical reasons the two fields have advanced in parallel, with little cross-fertilisation of ideas and techniques. The goal of this jointly supervised project is to combine the different expertise of our two groups to bring strongly interacting electrons into the mesoscopic regime. You will work both in St Andrews and at the spectacular new Harvard Nanoscience Center, performing pioneering experiments on the fabrication and measurement of correlated electron mesoscopic devices.
This project is offer in conjunction with Prof. Amir Yacoby at Harvard.
In this project, we aim to bridge the gap between two fields in which huge progress has been made over the past twenty years. In mesoscopic physics, the aim is to work with samples that are specially fabricated so that their physical size becomes comparable with one or more of the fundamental length scales of the underlying physics. In a metal this might be the mean free path, and in a superconductor it might be the coherence length or the penetration depth. So far, the vast majority of research into mesoscopic physics has been performed on traditional materials in which the electron-electron interactions are relatively weak. In parallel with these developments, equally rapid progress has been made on research into new materials with very strong electron-electron interactions, which lead to high quasiparticle masses and an exciting variety of metallic, superconducting and magnetic ground states. For technical reasons the two fields have advanced in parallel, with little cross-fertilisation of ideas and techniques. The goal of this jointly supervised project is to combine the different expertise of our two groups to bring strongly interacting electrons into the mesoscopic regime. You will work both in St Andrews and at the spectacular new Harvard Nanoscience Center, performing pioneering experiments on the fabrication and measurement of correlated electron mesoscopic devices.
Nanoscale inhomogeneity of correlated materials from spatially resolved ARPES
Baumberger, Dr Felix - fb40@st-andrews.ac.uk
Tamai, Dr Anna - at71@st-andrews.ac.uk
Electronic inhomogeneity and phase separation on the nanometer to micrometer length scale is ubiquitous in correlated electron systems and is generally accepted to have a defining influence on many macroscopic properties. However, progress in understanding phase separation or in exploiting it in designer materials has been limited by the profound experimental challenges and by the difficulty in modeling such systems alike. Nano-ARPES, a novel technique combining the energy and momentum resolution of angle-resolved photoemission with sub-100 nm spatial resolution holds the promise to meet this challenge.
In this project you will be involved in the development of a laser-based spatially resolved ARPES system at the university of St Andrews and you will use the most-advanced nano-focus synchrotron beamlines worldwide (currently at Elettra, Italy and Soleil, Paris, in the future also at Diamond, UK) for photoemission experiments on topical materials. First experiments will be on Mn-doped Sr3Ru2O7 and the Ru/Sr2RuO4 eutectic, for which some form of local inhomogeneity is already established.
For further information please contact Felix Baumberger
Tamai, Dr Anna - at71@st-andrews.ac.uk
Electronic inhomogeneity and phase separation on the nanometer to micrometer length scale is ubiquitous in correlated electron systems and is generally accepted to have a defining influence on many macroscopic properties. However, progress in understanding phase separation or in exploiting it in designer materials has been limited by the profound experimental challenges and by the difficulty in modeling such systems alike. Nano-ARPES, a novel technique combining the energy and momentum resolution of angle-resolved photoemission with sub-100 nm spatial resolution holds the promise to meet this challenge.
In this project you will be involved in the development of a laser-based spatially resolved ARPES system at the university of St Andrews and you will use the most-advanced nano-focus synchrotron beamlines worldwide (currently at Elettra, Italy and Soleil, Paris, in the future also at Diamond, UK) for photoemission experiments on topical materials. First experiments will be on Mn-doped Sr3Ru2O7 and the Ru/Sr2RuO4 eutectic, for which some form of local inhomogeneity is already established.
For further information please contact Felix Baumberger
Non-equilibrium and non-adiabatic effects in Bose-Einstein condensates
Hooley, Dr Chris - cah19@st-andrews.ac.uk
When a gas of bosonic atoms is cooled to very low temperatures, it undergoes a phase transition in which a macroscopic fraction of the atoms enters the lowest single-particle state of the system. This effect, called Bose-Einstein condensation, was predicted in 1924, but not directly observed until 1995 - the main difficulty being, of course, that gases don't tend to stay gaseous down to microkelvin temperatures unless cooled with great care! To this end, ingenious devices involving electromagnetic trapping and laser- and evaporative cooling have been devised. Recent experiments involve subjecting the atom cloud to laser standing waves (so-called "optical lattices") as well as the background trapping potential that stops the atoms from leaving the system. One of the most exciting opportunities presented by these set-ups is the opportunity to study quantum processes far from equilibrium: since the characteristic time-scales of the Bose gas are rather long, it's easy to make a "sudden" change in the laser field. Indeed, the study of such non-equilibrium effects is vital, as they are in fact the key to measuring the properties of such gases in the first place (via "time-of-flight" experiments). This theoretical project aims to put our understanding of non-equilibrium processes in trapped Bose- and Fermi gases on a firmer footing, addressing such issues as:
- atom-atom correlations during cloud expansion;
- anti-bound states from sudden quenching of the condensate;
- growth models for low-temperature Bose-Einstein fluids;
- measuring the BCS state for fermions.
Established relations with several experimental groups active in the field (e.g. the Inguscio group in Florence, the Hinds group at Imperial, and the Schmiedmayer group at Heidelberg) are expected to provide fruitful and up-to-date experimental information. The majority of the work will consist of pen-and-paper calculations, perhaps supplemented by some computational analysis.
When a gas of bosonic atoms is cooled to very low temperatures, it undergoes a phase transition in which a macroscopic fraction of the atoms enters the lowest single-particle state of the system. This effect, called Bose-Einstein condensation, was predicted in 1924, but not directly observed until 1995 - the main difficulty being, of course, that gases don't tend to stay gaseous down to microkelvin temperatures unless cooled with great care! To this end, ingenious devices involving electromagnetic trapping and laser- and evaporative cooling have been devised. Recent experiments involve subjecting the atom cloud to laser standing waves (so-called "optical lattices") as well as the background trapping potential that stops the atoms from leaving the system. One of the most exciting opportunities presented by these set-ups is the opportunity to study quantum processes far from equilibrium: since the characteristic time-scales of the Bose gas are rather long, it's easy to make a "sudden" change in the laser field. Indeed, the study of such non-equilibrium effects is vital, as they are in fact the key to measuring the properties of such gases in the first place (via "time-of-flight" experiments). This theoretical project aims to put our understanding of non-equilibrium processes in trapped Bose- and Fermi gases on a firmer footing, addressing such issues as:
- atom-atom correlations during cloud expansion;
- anti-bound states from sudden quenching of the condensate;
- growth models for low-temperature Bose-Einstein fluids;
- measuring the BCS state for fermions.
Established relations with several experimental groups active in the field (e.g. the Inguscio group in Florence, the Hinds group at Imperial, and the Schmiedmayer group at Heidelberg) are expected to provide fruitful and up-to-date experimental information. The majority of the work will consist of pen-and-paper calculations, perhaps supplemented by some computational analysis.
Nonequilibrium physics in many-body quantum optics systems
Keeling, Dr Jonathan - jmjk@st-andrews.ac.uk
The aim of this project is to explore phase transitions in non-equilibrium quantum systems, and in particular, those involving many body quantum optics that is readily accessible to current or future experiments with cold atoms or superconducting qubits.
The last few years have seen a growing range of experimental systems in which collective quantum optical effects can be studied, and which prompt important questions about the differences between "quantum" phase transitions in open and closed quantum systems, and whether open quantum systems can ever be described as displaying a quantum phase transition. In particular, experiments by the group of Esslinger in ETH have shown how cold atoms in an optical cavity subject to an external coherent pump can undergo a transition to a superradiant phase.
This project will consider related problems, in which different aspects of quantum phase transitions in non-equilibrium systems become accessible.
The aim of this project is to explore phase transitions in non-equilibrium quantum systems, and in particular, those involving many body quantum optics that is readily accessible to current or future experiments with cold atoms or superconducting qubits.
The last few years have seen a growing range of experimental systems in which collective quantum optical effects can be studied, and which prompt important questions about the differences between "quantum" phase transitions in open and closed quantum systems, and whether open quantum systems can ever be described as displaying a quantum phase transition. In particular, experiments by the group of Esslinger in ETH have shown how cold atoms in an optical cavity subject to an external coherent pump can undergo a transition to a superradiant phase.
This project will consider related problems, in which different aspects of quantum phase transitions in non-equilibrium systems become accessible.
Quantum phase transitions in two dimensional electron gases
Mackenzie, Prof Andy - apm9@st-andrews.ac.uk
This project is offer in conjunction with Prof. Amir Yacoby at Harvard.
In recent years there has been a resurgence of interest in strictly two-dimensional electron systems. The two-dimensional electron gas (2DEG) first came to prominence in semiconductor devices, on which famous discoveries such as the Integer and Fractional Quantum Hall Effects were made. Now, because of the discovery that 2DEGs exist in other material systems such as graphene and oxide multilayers, there is the promise of discovering rich new physics. Graphene is proving to be particularly interesting, with coupled bilayers showing a rich variety of quantum phases and phase transitions. It is possible that there are similarities with the behaviour seen in bulk materials such as Sr3Ru2O7 which consist of stacks of weakly coupled bilayers. This project is to study and understand the fascinating phase diagrams that can arise in such systems, and to assess the role that quantum fluctuations play in determining their fascinating properties. The work, which combines the expertise of two collaborating research groups, will be carried out both in St Andrews and at the new Harvard Nanoscience Center.
This project is offer in conjunction with Prof. Amir Yacoby at Harvard.
In recent years there has been a resurgence of interest in strictly two-dimensional electron systems. The two-dimensional electron gas (2DEG) first came to prominence in semiconductor devices, on which famous discoveries such as the Integer and Fractional Quantum Hall Effects were made. Now, because of the discovery that 2DEGs exist in other material systems such as graphene and oxide multilayers, there is the promise of discovering rich new physics. Graphene is proving to be particularly interesting, with coupled bilayers showing a rich variety of quantum phases and phase transitions. It is possible that there are similarities with the behaviour seen in bulk materials such as Sr3Ru2O7 which consist of stacks of weakly coupled bilayers. This project is to study and understand the fascinating phase diagrams that can arise in such systems, and to assess the role that quantum fluctuations play in determining their fascinating properties. The work, which combines the expertise of two collaborating research groups, will be carried out both in St Andrews and at the new Harvard Nanoscience Center.
Search for Novel Metamagnetic Quantum Criticality and Phase Formation
Mackenzie, Prof Andy - apm9@st-andrews.ac.uk
Rost, Dr Andreas - ar35@st-andrews.ac.uk
In recent years there has been a resurgence of interest in the phenomenon of itinerant metamagnetism, in which metallic systems undergo a strong, non-linear change in magnetic moment in an applied magnetic field. A number of interesting observations have been made, but arguably the most prominent discoveries are those of an electronic liquid-crystal like phase in Sr3Ru2O7 [1] and re-entrant superconducitivity in URhGe [2]. Observations like these motivate the search for other materials displaying metamagnetism that might be driven quantum critical. This is essentially a chemical physics PhD project, involving decisions about material classes to study, chemical synthesis of appropriate materials, high purity crystal growth and, ultimately, low temperature measurement.
[1] R.A. Borzi, S.A. Grigera, J. Farrell, R.S. Perry, S. Lister, S.L. Lee, D.A. Tennant, Y. Maeno & A.P. Mackenzie, Science 315, 214 (2007)
[2] F. Lévy, I. Sheikin & A.D. Huxley, Science 309, 1343 (2005).
and references therein
Rost, Dr Andreas - ar35@st-andrews.ac.uk
In recent years there has been a resurgence of interest in the phenomenon of itinerant metamagnetism, in which metallic systems undergo a strong, non-linear change in magnetic moment in an applied magnetic field. A number of interesting observations have been made, but arguably the most prominent discoveries are those of an electronic liquid-crystal like phase in Sr3Ru2O7 [1] and re-entrant superconducitivity in URhGe [2]. Observations like these motivate the search for other materials displaying metamagnetism that might be driven quantum critical. This is essentially a chemical physics PhD project, involving decisions about material classes to study, chemical synthesis of appropriate materials, high purity crystal growth and, ultimately, low temperature measurement.
[1] R.A. Borzi, S.A. Grigera, J. Farrell, R.S. Perry, S. Lister, S.L. Lee, D.A. Tennant, Y. Maeno & A.P. Mackenzie, Science 315, 214 (2007)
[2] F. Lévy, I. Sheikin & A.D. Huxley, Science 309, 1343 (2005).
and references therein
Spectroscopic STM studies of iron-based superconductors
Baumberger, Dr Felix - fb40@st-andrews.ac.uk
Tamai, Dr Anna - at71@st-andrews.ac.uk
The recent discovery of high-temperature super-conductivity in iron-based compounds challenges our understanding of interacting electrons systems. In this project you will investigate the intriguing electronic properties of ferrous superconductors using spectroscopic imaging scanning tunneling microscopy. Initially, you will focus on the ‘11’ family of iron-chalcogenides Fe(Se/Te) and investigate their electronic structure by imaging the interference pattern of wave-like quasiparticle excitations. Later, you will extend these studies to iron-arsenides and doped chalcogenides in order to develop an understanding of the similarities and differences between various iron-based superconductors.
All experiments will be performed in-house on a new low-temperature (< 1 K) STM, which is currently being commissioned by our group and will be performed in close collaboration with other group members working on complementary angle resolved photoemission (ARPES) studies on the same samples. This approach promises unique insight into topical materials with fascinating properties.
For further information please contact Felix Baumberger
Tamai, Dr Anna - at71@st-andrews.ac.uk
The recent discovery of high-temperature super-conductivity in iron-based compounds challenges our understanding of interacting electrons systems. In this project you will investigate the intriguing electronic properties of ferrous superconductors using spectroscopic imaging scanning tunneling microscopy. Initially, you will focus on the ‘11’ family of iron-chalcogenides Fe(Se/Te) and investigate their electronic structure by imaging the interference pattern of wave-like quasiparticle excitations. Later, you will extend these studies to iron-arsenides and doped chalcogenides in order to develop an understanding of the similarities and differences between various iron-based superconductors.
All experiments will be performed in-house on a new low-temperature (< 1 K) STM, which is currently being commissioned by our group and will be performed in close collaboration with other group members working on complementary angle resolved photoemission (ARPES) studies on the same samples. This approach promises unique insight into topical materials with fascinating properties.
For further information please contact Felix Baumberger
Spin-helical surface states on topological insulators
Baumberger, Dr Felix - fb40@st-andrews.ac.uk
King, Dr Phil - pdk6@st-andrews.ac.uk
It had been assumed since the 1930’s that ‘band insulators’ - materials in which an energy gap is created by the periodic potential of the ion cores - were fully understood. Only thanks to very recent theoretical work motivated by the physics of graphene, it became clear that these materials fall into two distinct classes: conventional band insulators and an exciting new form dubbed ‘topological insulators’ characterized by the existence of metallic surface states with a Dirac dispersion and helical spin-structure. The highly unusual properties of these surface states, such as their unconventional spin texture and predicted protection from backscattering, render topological insulators interesting for novel applications in spintronics or magnetoelectric devices. Moreover, there are exciting proposals to utilize the special properties of topological surface states for novel schemes in quantum computing.
In this project you will study the Dirac dispersion of topological surface states directly using angle-resolved photoemission (ARPES). The experiments will be performed in our state-of-the-art spectroscopy lab at the University of St Andrews as well as at synchrotron light sources in Europe and the US, and will include the preparation and study of magnetic or superconducting thin films on surfaces of topological insulators.
For further information please contact Felix Baumberger
King, Dr Phil - pdk6@st-andrews.ac.uk
It had been assumed since the 1930’s that ‘band insulators’ - materials in which an energy gap is created by the periodic potential of the ion cores - were fully understood. Only thanks to very recent theoretical work motivated by the physics of graphene, it became clear that these materials fall into two distinct classes: conventional band insulators and an exciting new form dubbed ‘topological insulators’ characterized by the existence of metallic surface states with a Dirac dispersion and helical spin-structure. The highly unusual properties of these surface states, such as their unconventional spin texture and predicted protection from backscattering, render topological insulators interesting for novel applications in spintronics or magnetoelectric devices. Moreover, there are exciting proposals to utilize the special properties of topological surface states for novel schemes in quantum computing.
In this project you will study the Dirac dispersion of topological surface states directly using angle-resolved photoemission (ARPES). The experiments will be performed in our state-of-the-art spectroscopy lab at the University of St Andrews as well as at synchrotron light sources in Europe and the US, and will include the preparation and study of magnetic or superconducting thin films on surfaces of topological insulators.
For further information please contact Felix Baumberger
Studying Magnetic Recording Media using Neutrons and Synchrotron Radiation
Lee, Prof Steve - sl10@st-andrews.ac.uk
We are currently working in a close collaboration with Hitachi Research Labs, San Hose, CA to look at the magnetic structure of magnetic recording media at the sub-10 nm length scale. Magnetic recording media, used in magnetic disk drives, are of extreme commercial and technological importance and lie at the centre of many common devices including computers, video recorders and ipods. The smallest functional magnetic element in these materials, the magnetic grain, is typically about 10 nm in diameter, yet there are very few techniques that can probe the magnetic structure at these length scales. Among these are neutron and synchrotron radiation techniques. The group at St Andrews has a long reputation of carrying out high quality research using some of the world's best facilities for condensed matter research. This includes the use of international facilities for the generation of neutrons and muons such as the Institut Laue Langevin in Grenoble, France, or the Paul Scherrer Institute, Switzerland.
This project with Hitachi is supported by an EPSRC grant over the next three years which includes a PhD project studentship. The student will work closely with an experienced post-doctoral researcher employed on the same grant. We aim to bring the scientific rigour and attention to detail that we use in our fundamental research to this more applied project. This has already brought us to the forefront of worldwide research in this area and there is great opportunity for the further exploitation of the approaches we have developed. We are currently working on the very latest research materials from Hitachi and thus have the possibility of making valuable contributions to future materials development that could impact directly on technology.
The PhD position offers a great opportunity for a highly motivated student to receive outstanding training in advanced techniques at some of the world’s leading central facilities in France, Switzlerland, Germany and the UK. There also exists the possibility to spend periods at the Hitachi research centre in San Jose.
Please make any informal enquiries to Professor Steve Lee, sl10@st-and.ac.uk.
We are currently working in a close collaboration with Hitachi Research Labs, San Hose, CA to look at the magnetic structure of magnetic recording media at the sub-10 nm length scale. Magnetic recording media, used in magnetic disk drives, are of extreme commercial and technological importance and lie at the centre of many common devices including computers, video recorders and ipods. The smallest functional magnetic element in these materials, the magnetic grain, is typically about 10 nm in diameter, yet there are very few techniques that can probe the magnetic structure at these length scales. Among these are neutron and synchrotron radiation techniques. The group at St Andrews has a long reputation of carrying out high quality research using some of the world's best facilities for condensed matter research. This includes the use of international facilities for the generation of neutrons and muons such as the Institut Laue Langevin in Grenoble, France, or the Paul Scherrer Institute, Switzerland.
This project with Hitachi is supported by an EPSRC grant over the next three years which includes a PhD project studentship. The student will work closely with an experienced post-doctoral researcher employed on the same grant. We aim to bring the scientific rigour and attention to detail that we use in our fundamental research to this more applied project. This has already brought us to the forefront of worldwide research in this area and there is great opportunity for the further exploitation of the approaches we have developed. We are currently working on the very latest research materials from Hitachi and thus have the possibility of making valuable contributions to future materials development that could impact directly on technology.
The PhD position offers a great opportunity for a highly motivated student to receive outstanding training in advanced techniques at some of the world’s leading central facilities in France, Switzlerland, Germany and the UK. There also exists the possibility to spend periods at the Hitachi research centre in San Jose.
Please make any informal enquiries to Professor Steve Lee, sl10@st-and.ac.uk.
Superconductivity and Spin-Orbit Coupling in Sr2RuO4
Grigera, Dr Santiago - sag2@st-andrews.ac.uk
Mackenzie, Prof Andy - apm9@st-andrews.ac.uk
The superconductivity of Sr2RuO4 was discovered nearly fifteen years ago, but continues to be a major open topic. The symmetry of the superconducting state seems to be highly unusual, with pairing in the spin triplet channel, in analogy to that in the famous superfluid 3He [1]. The material also offers the intriguing possibility, long-term, of providing a platform for the implementation of exotic schemes for ‘non abelian quantum computing’ [2]. In order to tell whether that is an achievable goal, much more needs to be understood. Does the superconducting state contain the domains predicted by some theories and inferred from some experimental results? If so, can we find out how to control them? Can mesoscopic patterning be performed without destroying the fragile superconductivity? How big is spin-orbit coupling and what role does it play? As a first step to answering these questions, we have recently made what we believe to be the best single crystals ever grown of Sr2RuO4. These will enable us to instigate some ambitious experiments both in-house and with our collaborators in Bath, Cambridge, Harvard and Kyoto. The project will involve working on one or more of the topics listed above, according to unfolding priorities.
[1] A.P. Mackenzie and Y. Maeno, Rev. Mod. Phys. 75, 657 (2003)
[2] For a series of on-line talks on the issue see: online.itp.ucsb.edu/online/chiralsc_m07
Mackenzie, Prof Andy - apm9@st-andrews.ac.uk
The superconductivity of Sr2RuO4 was discovered nearly fifteen years ago, but continues to be a major open topic. The symmetry of the superconducting state seems to be highly unusual, with pairing in the spin triplet channel, in analogy to that in the famous superfluid 3He [1]. The material also offers the intriguing possibility, long-term, of providing a platform for the implementation of exotic schemes for ‘non abelian quantum computing’ [2]. In order to tell whether that is an achievable goal, much more needs to be understood. Does the superconducting state contain the domains predicted by some theories and inferred from some experimental results? If so, can we find out how to control them? Can mesoscopic patterning be performed without destroying the fragile superconductivity? How big is spin-orbit coupling and what role does it play? As a first step to answering these questions, we have recently made what we believe to be the best single crystals ever grown of Sr2RuO4. These will enable us to instigate some ambitious experiments both in-house and with our collaborators in Bath, Cambridge, Harvard and Kyoto. The project will involve working on one or more of the topics listed above, according to unfolding priorities.
[1] A.P. Mackenzie and Y. Maeno, Rev. Mod. Phys. 75, 657 (2003)
[2] For a series of on-line talks on the issue see: online.itp.ucsb.edu/online/chiralsc_m07
The QuVis quantum mechanics visualization project
Kohnle, Dr Antje - ak81@st-andrews.ac.uk
The University of St Andrews QuVis project aims to enhance student conceptual understanding of quantum mechanics through the development of animations and visualizations based on outcomes of education research into student difficulties in quantum mechanics. Evaluation goes hand-in-hand with development, and has been used to optimize interface design and content. However, no work has been done on optimizing the format of the animations to enhance student engagement and learning.
This project will use education research literature and pilot studies to develop a number of animations each in different formats (e.g. including additional interactive elements such as questions or explanation levels). A multi-institutional study will then investigate the influence of animation format on student engagement and learning. Outcomes will be used to optimize the format of all animations.
The project will also include work to support curriculum reform in quantum mechanics. The traditional, historical approach to teaching quantum mechanics has been questioned in recent years in the light of changing applications of quantum physics and emerging fields such as quantum information theory. Several textbooks now start from simple two-level systems (such as photon polarization) and develop the theory using discrete systems. One limitation of such an approach is that it can appear more abstract and link less easily to previously encountered physics. This project will support the development of a revised quantum mechanics curriculum by developing animations and visualizations for such a curriculum.
The QuVis animations and visualizations: http://www.st-andrews.ac.uk/~qmanim
The University of St Andrews QuVis project aims to enhance student conceptual understanding of quantum mechanics through the development of animations and visualizations based on outcomes of education research into student difficulties in quantum mechanics. Evaluation goes hand-in-hand with development, and has been used to optimize interface design and content. However, no work has been done on optimizing the format of the animations to enhance student engagement and learning.
This project will use education research literature and pilot studies to develop a number of animations each in different formats (e.g. including additional interactive elements such as questions or explanation levels). A multi-institutional study will then investigate the influence of animation format on student engagement and learning. Outcomes will be used to optimize the format of all animations.
The project will also include work to support curriculum reform in quantum mechanics. The traditional, historical approach to teaching quantum mechanics has been questioned in recent years in the light of changing applications of quantum physics and emerging fields such as quantum information theory. Several textbooks now start from simple two-level systems (such as photon polarization) and develop the theory using discrete systems. One limitation of such an approach is that it can appear more abstract and link less easily to previously encountered physics. This project will support the development of a revised quantum mechanics curriculum by developing animations and visualizations for such a curriculum.
The QuVis animations and visualizations: http://www.st-andrews.ac.uk/~qmanim
Ultrafast Photophysics of Organic Semiconductors
Samuel, Prof Ifor - idws@st-andrews.ac.uk
This project will explore the physics of remarkable plastic-like semiconductors, such as light-emitting polymers. These materials are model one-dimensional systems and this strongly influences their physics – for example it means that excitons are strongly bound and that there is a substantial distortion of the material when it is excited. The purpose of this project is to study the nature of the excited states in these materials and how they evolve when the sample is excited by light. The initial rearrangement of the molecules occurs on a timescale of 100 femtoseconds. Remarkably we can make measurements on this timescale using advanced femtosecond lasers. We wish to explore how the excited states form and then decay, and how these processes relate to the structure of the material. The results will help understand light emission and amplification, and complementary theoretical work is underway at Heriot-Watt University by Prof. Ian Galbraith.
This project will explore the physics of remarkable plastic-like semiconductors, such as light-emitting polymers. These materials are model one-dimensional systems and this strongly influences their physics – for example it means that excitons are strongly bound and that there is a substantial distortion of the material when it is excited. The purpose of this project is to study the nature of the excited states in these materials and how they evolve when the sample is excited by light. The initial rearrangement of the molecules occurs on a timescale of 100 femtoseconds. Remarkably we can make measurements on this timescale using advanced femtosecond lasers. We wish to explore how the excited states form and then decay, and how these processes relate to the structure of the material. The results will help understand light emission and amplification, and complementary theoretical work is underway at Heriot-Watt University by Prof. Ian Galbraith.
Photonics
Advanced Imaging for the Biomedical Sciences (with Dr F Gunn-Moore, School of Biology)
Cizmar, Dr Tomas - tc51@st-andrews.ac.uk
Dholakia, Prof Kishan - kd1@st-andrews.ac.uk
the aim of this project is to explore new routes for imaging both in vitro and in vivo using concepts of light transmission through disorder. In turn this will allow us to shape light at will for example at the end of an optical fibre and use this perhaps in an endoscopic scenarios. Other forms of microscopy to consider will involve using a light sheet for imaging larger biological systems (eg embryos). The study will involve advanced photonics, numerical studies and practical work. The research will also investigate strategies to image beyond the diffraction limit. Samples under investigation will include tissue and, at later stages of the work, potentially neuronal cells/tissue to target advanced understanding of neurological disease using these methods.
Dholakia, Prof Kishan - kd1@st-andrews.ac.uk
the aim of this project is to explore new routes for imaging both in vitro and in vivo using concepts of light transmission through disorder. In turn this will allow us to shape light at will for example at the end of an optical fibre and use this perhaps in an endoscopic scenarios. Other forms of microscopy to consider will involve using a light sheet for imaging larger biological systems (eg embryos). The study will involve advanced photonics, numerical studies and practical work. The research will also investigate strategies to image beyond the diffraction limit. Samples under investigation will include tissue and, at later stages of the work, potentially neuronal cells/tissue to target advanced understanding of neurological disease using these methods.
Biophysical Aspects of Photodynamic Therapy (Ninewells Hospital, Dundee)
Brown, Dr Tom - ctab@st-andrews.ac.uk
Wood, Dr Kenneth - kw25@st-andrews.ac.uk
Photodynamic Therapy (PDT) is a treatment for cancer that involves light-activation of a photosensitiser and causes cell death by release of singlet oxygen and free radicals. The Scottish PDT Centre was established in Ninewells Hospital, Dundee in 2000 thanks to a generous donation from the Barbara Stewart Charitable Trust. Since its introduction in Dundee, over 2,000 treatments have been carried out. The photosensiters used for PDT also have the property that they fluoresce and so they can be used for photodiagnosis (PD), which is performed at the Scottish PDT Centre to direct the surgeon towards tissue that is likely to be cancerous.
The purpose of the proposed PhD program is to gain a fuller understanding of the interaction between the incident light and the tumour. Optimal treatment regimes have not been established. We would like to be able to model both PDT and PD. To assist in this, we propose to develop theoretical radiation transfer models using Monte Carlo techniques in order to simulate the incident light and the fluorescent emission. This will be done for the range of tissue types where PDT is performed in Dundee. This includes skin (the most accessible), the oral cavity, the brain and bladder.
The work will also find application in a wide range of other areas in the drive towards minimally invasive and highly targeted therapies. In addition to the PDT described above, the techniques can be applied to so-called ‘caged compounds’ that are a range of biologically active compounds that are activated with light. In order to apply such compounds within a therapeutic environment, understanding the light tissue interactions is of key importance.
Light distribution measurements will be made around a range of light delivery devices, including cylindrical diffusers and miniature balloons filled with light-scattering media. Further measurements will be carried out using optical fibres embedded in tissue samples and using ultrashort pulses to probe two-photon activation at depth within the body. Fluorescent emission spectra will also be measured using a specially constructed optical biopsy system.
This project provides many opportunities for the student to study PDT and other light activated therapies from theoretical, experimental, and clinical perspectives.
There will be joint supervision from Dr Harry Moseley, who is Technical & Scientific Director of the Scottish PDT Centre and Honorary Reader at the University of Dundee, and Drs Tom Brown and Kenny Wood, who are Lecturers in the Department of Physics and Astronomy at the University of St Andrews. Dr Wood will supervise the theoretical aspects of the PhD (Monte Carlo radiation transfer), Dr Brown the experimental light tissue studies and Dr Moseley will supervise the clinical applications at Ninewells Hospital.
Wood, Dr Kenneth - kw25@st-andrews.ac.uk
Photodynamic Therapy (PDT) is a treatment for cancer that involves light-activation of a photosensitiser and causes cell death by release of singlet oxygen and free radicals. The Scottish PDT Centre was established in Ninewells Hospital, Dundee in 2000 thanks to a generous donation from the Barbara Stewart Charitable Trust. Since its introduction in Dundee, over 2,000 treatments have been carried out. The photosensiters used for PDT also have the property that they fluoresce and so they can be used for photodiagnosis (PD), which is performed at the Scottish PDT Centre to direct the surgeon towards tissue that is likely to be cancerous.
The purpose of the proposed PhD program is to gain a fuller understanding of the interaction between the incident light and the tumour. Optimal treatment regimes have not been established. We would like to be able to model both PDT and PD. To assist in this, we propose to develop theoretical radiation transfer models using Monte Carlo techniques in order to simulate the incident light and the fluorescent emission. This will be done for the range of tissue types where PDT is performed in Dundee. This includes skin (the most accessible), the oral cavity, the brain and bladder.
The work will also find application in a wide range of other areas in the drive towards minimally invasive and highly targeted therapies. In addition to the PDT described above, the techniques can be applied to so-called ‘caged compounds’ that are a range of biologically active compounds that are activated with light. In order to apply such compounds within a therapeutic environment, understanding the light tissue interactions is of key importance.
Light distribution measurements will be made around a range of light delivery devices, including cylindrical diffusers and miniature balloons filled with light-scattering media. Further measurements will be carried out using optical fibres embedded in tissue samples and using ultrashort pulses to probe two-photon activation at depth within the body. Fluorescent emission spectra will also be measured using a specially constructed optical biopsy system.
This project provides many opportunities for the student to study PDT and other light activated therapies from theoretical, experimental, and clinical perspectives.
There will be joint supervision from Dr Harry Moseley, who is Technical & Scientific Director of the Scottish PDT Centre and Honorary Reader at the University of Dundee, and Drs Tom Brown and Kenny Wood, who are Lecturers in the Department of Physics and Astronomy at the University of St Andrews. Dr Wood will supervise the theoretical aspects of the PhD (Monte Carlo radiation transfer), Dr Brown the experimental light tissue studies and Dr Moseley will supervise the clinical applications at Ninewells Hospital.
Explosive Vapor Sensors
Turnbull, Dr Graham - gat@st-andrews.ac.uk
Technologies for explosive detection are widely required in for clearance of land mines and submunitions, for detection of improvised explosive devices in war zones and counter terrorism scenarios. One approach to explosive detection is to sense the very dilute vapors of explosive molecules that exist around a source of explosives. The established approach for this is to use sniffer dogs to smell for the vapors.
In many situations it would be attractive to have a compact technology-based alternative to the sniffer dog. We are developing artificial noses based on organic semiconductors that can radpidly detect trace concentrations of TNT-like vapors. This project will develop organic semiconductor laser sensors for vapor detection and understanding the underlying physics of the interactions involved.
Technologies for explosive detection are widely required in for clearance of land mines and submunitions, for detection of improvised explosive devices in war zones and counter terrorism scenarios. One approach to explosive detection is to sense the very dilute vapors of explosive molecules that exist around a source of explosives. The established approach for this is to use sniffer dogs to smell for the vapors.
In many situations it would be attractive to have a compact technology-based alternative to the sniffer dog. We are developing artificial noses based on organic semiconductors that can radpidly detect trace concentrations of TNT-like vapors. This project will develop organic semiconductor laser sensors for vapor detection and understanding the underlying physics of the interactions involved.
Hawking radiation in the laboratory
Koenig, Dr Frieder - fewk@st-andrews.ac.uk
Black holes can be understood in a simple picture: Imagine a river flowing towards a waterfall with ever increasing flow speed. Also imagine fishes in the river swimming upstream. At some position in the river the maximum speed of the fish will equal the flow speed and all fish beyond that "point of no return" will be flushed into the waterfall. Here the flow speed corresponds to the gravity of a black hole and the point of no return to the event horizon.
Arguably the most facinating aspects of astronomical black holes is the emission of Hawking radiation from the event horizon, an intriguing quantum effect combining gravity, thermodynamics and quantum mechanics.
Unfortunately, the astrophysical Hawking radiation is far too weak to ever being detected directly. Recently, however, we have invented a method to create moving artificial event horizons with short pulses in optical fibers. Moreover, the expected Hawking radiation is strong enough to be detectable with single photon coincindence counting.
The idea of the PhD programme is the detection and characterization of this elusive Hawking radiation for the first time. The work has already gained momentum in our group and a setup is built using optical pulses of just a few cycles pulse length. In addition we will explore similar quantum effects such as the Unruh effect and the dynamical Casimir effect.
Black holes can be understood in a simple picture: Imagine a river flowing towards a waterfall with ever increasing flow speed. Also imagine fishes in the river swimming upstream. At some position in the river the maximum speed of the fish will equal the flow speed and all fish beyond that "point of no return" will be flushed into the waterfall. Here the flow speed corresponds to the gravity of a black hole and the point of no return to the event horizon.
Arguably the most facinating aspects of astronomical black holes is the emission of Hawking radiation from the event horizon, an intriguing quantum effect combining gravity, thermodynamics and quantum mechanics.
Unfortunately, the astrophysical Hawking radiation is far too weak to ever being detected directly. Recently, however, we have invented a method to create moving artificial event horizons with short pulses in optical fibers. Moreover, the expected Hawking radiation is strong enough to be detectable with single photon coincindence counting.
The idea of the PhD programme is the detection and characterization of this elusive Hawking radiation for the first time. The work has already gained momentum in our group and a setup is built using optical pulses of just a few cycles pulse length. In addition we will explore similar quantum effects such as the Unruh effect and the dynamical Casimir effect.
Integrated Magnetic Resonance Doctoral Training Centre
Smith, Dr Graham - gms@st-andrews.ac.uk
The new EPSRC Doctoral Training Centre in Integrated Magnetic Resonance is a collaboration between 6 of the UK's leading Universities in Advanced Magnetic Resonance Instrumentation and Techniques and includes St. Andrews, Dundee, Aberdeen, Warwick, Nottingham and Southampton.
The aim is to provide a coherent training program for doctoral students whilst working on new research topics in instrumentation and methodology, associated with Magnetic Resonance Imaging, Electron Magnetic Resonance, Nuclear Magnetic Resonance and Dynamic Nuclear Polarisation (which collectively represent £multi-Billion annual markets). Training is delivered from all centres, through residential workshops and over the Access Grid, primarily in the first two years of study.
Funded 4 year PhDs include fees and maintenance of £14000 (tax free) per annum as well as an enhanced travel budget. All PhDs will have internal and external mentors from other centres.
At St Andrews, PhD projects are available on themes associated with major advances in Electron Magnetic Resonance and Dynamic Nuclear Polarisation and are likely to involve collaborations with other centres and other interdisciplinary groups.
PhD topics are likely to involve a combination of instrumental, methodological and computational techniques that would normally be associated with Basic Technology programs.
Representative PhDs from all 6 centres are listed on www.imr-cdt.ac.uk, but other PhD topics may be available on request.
For PhDs at St Andrews, applications can be made directly to St Andrews or via Warwick where the DTC program is administered.
The new EPSRC Doctoral Training Centre in Integrated Magnetic Resonance is a collaboration between 6 of the UK's leading Universities in Advanced Magnetic Resonance Instrumentation and Techniques and includes St. Andrews, Dundee, Aberdeen, Warwick, Nottingham and Southampton.
The aim is to provide a coherent training program for doctoral students whilst working on new research topics in instrumentation and methodology, associated with Magnetic Resonance Imaging, Electron Magnetic Resonance, Nuclear Magnetic Resonance and Dynamic Nuclear Polarisation (which collectively represent £multi-Billion annual markets). Training is delivered from all centres, through residential workshops and over the Access Grid, primarily in the first two years of study.
Funded 4 year PhDs include fees and maintenance of £14000 (tax free) per annum as well as an enhanced travel budget. All PhDs will have internal and external mentors from other centres.
At St Andrews, PhD projects are available on themes associated with major advances in Electron Magnetic Resonance and Dynamic Nuclear Polarisation and are likely to involve collaborations with other centres and other interdisciplinary groups.
PhD topics are likely to involve a combination of instrumental, methodological and computational techniques that would normally be associated with Basic Technology programs.
Representative PhDs from all 6 centres are listed on www.imr-cdt.ac.uk, but other PhD topics may be available on request.
For PhDs at St Andrews, applications can be made directly to St Andrews or via Warwick where the DTC program is administered.
Microphotonics - general enquiries
Krauss, Prof Thomas - tfk@st-andrews.ac.uk
We are always keen to hear from students interested in pursuing a PhD in one of our research areas, whether or not a particular project is available. Our typical funding sources make it easier to support UK and EU students, but exceptional students from overseas (China, India etc.) are also encouraged to apply. Most notably, they can apply for support via SUPA with a deadline at the end of January, or ORSAS with a deadline in March.
We are always keen to hear from students interested in pursuing a PhD in one of our research areas, whether or not a particular project is available. Our typical funding sources make it easier to support UK and EU students, but exceptional students from overseas (China, India etc.) are also encouraged to apply. Most notably, they can apply for support via SUPA with a deadline at the end of January, or ORSAS with a deadline in March.
MM-wave Radar, Components and Techniques
Smith, Dr Graham - gms@st-andrews.ac.uk
MM-waves represent the area of the electromagnetic spectrum that sits between microwaves and Terahertz frequencies. It is the part of the spectrum where electronics meets optics and a wide variety of physical techniques are used to design components and systems. MM-waves are used in high resolution radar, fusion diagnostics, earth resource studies, magnetic resonance and security systems.
The mm-wave group at St Andrews is one of the largest and most well established groups in this field in the UK, and has a strong track record in designing components, sub-systems and full system. Much recent work ahas concentrated on developing radar imaging systems for earth resource studies (imaging volcanos, monitoring rainfall) and for various security related systems.
There is also a very strong program in mm-wave magnetic resonance.
A variety of PhD topics are always available and any interested student should get in touch with Dr Graham Smith in the first instance.
MM-waves represent the area of the electromagnetic spectrum that sits between microwaves and Terahertz frequencies. It is the part of the spectrum where electronics meets optics and a wide variety of physical techniques are used to design components and systems. MM-waves are used in high resolution radar, fusion diagnostics, earth resource studies, magnetic resonance and security systems.
The mm-wave group at St Andrews is one of the largest and most well established groups in this field in the UK, and has a strong track record in designing components, sub-systems and full system. Much recent work ahas concentrated on developing radar imaging systems for earth resource studies (imaging volcanos, monitoring rainfall) and for various security related systems.
There is also a very strong program in mm-wave magnetic resonance.
A variety of PhD topics are always available and any interested student should get in touch with Dr Graham Smith in the first instance.
Nano-technologies and Nano-particles
André, Dr Pascal - pa11@st-andrews.ac.uk
Nano-technologies and nano-particles are of broad interest both for fundamental science investigations and for various applications ranging from hard drive, light emitting diodes and solar cells, to biological tagging. Colloidal syntheses provide access to a large range of parameters allowing cheap but drastic control over chemical compositions, crystalline structures, shapes and surface states, while retaining solution based low cost processes. Materials under investigation include metal, semiconductor and magnetic materials, … however understanding and fine tuning the properties of these nano-elements remain to be improved for further development of their applications.
Our interests involve both synthesis and characterisation of new nano-elements with emphasis on core-shell structures and hybrid nano-materials for the design of specific physical properties. Various experimental projects are currently being developed requiring the group members to be at the interface of at least Physics and Chemistry when not biomedicine. Most of the projects involve collaborations in St Andrews, in the UK and abroad and when possible we aim at joining experimental and numerical contributions to better understand and control material properties.
Candidates should have a solid scientific background with a 1st class MSc or equivalent and a strong interest in at least two of the following Physics, Chemistry, Material Sciences, Chemical-Physics, Chemical-Engineering and Pharmarcy along with a serious commitment to collaborative and interdisciplinary research. Information requests & CVs should be sent to Pascal.Andre@st-and.ac.uk.
Nano-technologies and nano-particles are of broad interest both for fundamental science investigations and for various applications ranging from hard drive, light emitting diodes and solar cells, to biological tagging. Colloidal syntheses provide access to a large range of parameters allowing cheap but drastic control over chemical compositions, crystalline structures, shapes and surface states, while retaining solution based low cost processes. Materials under investigation include metal, semiconductor and magnetic materials, … however understanding and fine tuning the properties of these nano-elements remain to be improved for further development of their applications.
Our interests involve both synthesis and characterisation of new nano-elements with emphasis on core-shell structures and hybrid nano-materials for the design of specific physical properties. Various experimental projects are currently being developed requiring the group members to be at the interface of at least Physics and Chemistry when not biomedicine. Most of the projects involve collaborations in St Andrews, in the UK and abroad and when possible we aim at joining experimental and numerical contributions to better understand and control material properties.
Candidates should have a solid scientific background with a 1st class MSc or equivalent and a strong interest in at least two of the following Physics, Chemistry, Material Sciences, Chemical-Physics, Chemical-Engineering and Pharmarcy along with a serious commitment to collaborative and interdisciplinary research. Information requests & CVs should be sent to Pascal.Andre@st-and.ac.uk.
Nonlinear Optical Micromanipulation
Dholakia, Prof Kishan - kd1@st-andrews.ac.uk
New uses of trapped colloid as nonlinear media and uses for observations of soliton-like waves and new forms of in-situ imaging as well as nonlinear processes (eg 4 wave mixing). This is a very exciting project based on novel ordering of colloidal particles in the presence of light fields as well as the use of these colloids as new media for nonlinear effects.
New uses of trapped colloid as nonlinear media and uses for observations of soliton-like waves and new forms of in-situ imaging as well as nonlinear processes (eg 4 wave mixing). This is a very exciting project based on novel ordering of colloidal particles in the presence of light fields as well as the use of these colloids as new media for nonlinear effects.
Optical excitation of new drugs
Brown, Dr Tom - ctab@st-andrews.ac.uk
Caged compounds are biologically active molecules that have had their functionality blocked by the addition of a chemical group. A flash of light at the right wavelength removes this caging group switching on the functionality of the drug. Working closely with collaborators in Oxford we are exploring how we can combine advanced photonic techniques with the action of these drugs to permit, for example different colours to activate different drugs in the same system. We would also like to explore the interaction of short pulses with these drugs to further enhance the possibility of their activation in experimental systems, and ultimately within living tissue. AT this stage some of our research is focussed on the application of these techniques to problems in neuroscience including initial attempts at better understanding the physical basis of memory.
Caged compounds are biologically active molecules that have had their functionality blocked by the addition of a chemical group. A flash of light at the right wavelength removes this caging group switching on the functionality of the drug. Working closely with collaborators in Oxford we are exploring how we can combine advanced photonic techniques with the action of these drugs to permit, for example different colours to activate different drugs in the same system. We would also like to explore the interaction of short pulses with these drugs to further enhance the possibility of their activation in experimental systems, and ultimately within living tissue. AT this stage some of our research is focussed on the application of these techniques to problems in neuroscience including initial attempts at better understanding the physical basis of memory.
Optical manipulation: air/vacuum trapping for cavity optomechanics
Dholakia, Prof Kishan - kd1@st-andrews.ac.uk
Mazilu, Dr Michael - mm17@st-andrews.ac.uk
Optical trapping leads to the confinement of microscopic and nanoscopic objects using light. In the domain of optomechanics we would like to cool small "trapped" mechanical oscillators down to the quantum regime. This project aims to experimentally explore new ways to levitate and trap microparticles in air and vacuum. The ultimate aim is to slow down or 'cool' spheres to the ground state of motion. The topic is currently one of the most exciting and rapidly growing areas of physics and will involve both theory and experiment.
Mazilu, Dr Michael - mm17@st-andrews.ac.uk
Optical trapping leads to the confinement of microscopic and nanoscopic objects using light. In the domain of optomechanics we would like to cool small "trapped" mechanical oscillators down to the quantum regime. This project aims to experimentally explore new ways to levitate and trap microparticles in air and vacuum. The ultimate aim is to slow down or 'cool' spheres to the ground state of motion. The topic is currently one of the most exciting and rapidly growing areas of physics and will involve both theory and experiment.
Organic lasers and optical amplifiers
Samuel, Prof Ifor - idws@st-andrews.ac.uk
We have demonstrated that organic semiconductors can make high gain optical amplifiers. Optical amplifiers are widely used to compensate transmission and splitting losses, and organic semiconductors have excellent compatibility with plastic optical fibre. We wish to explore the dynamics of organic lasers and amplifiers using a state of the art femtosecond laser facility. By understanding how current materials and devices work, we aim to develop a new generation of devices capable of, for example, all-optical switching.
We have demonstrated that organic semiconductors can make high gain optical amplifiers. Optical amplifiers are widely used to compensate transmission and splitting losses, and organic semiconductors have excellent compatibility with plastic optical fibre. We wish to explore the dynamics of organic lasers and amplifiers using a state of the art femtosecond laser facility. By understanding how current materials and devices work, we aim to develop a new generation of devices capable of, for example, all-optical switching.
Organic light-emitting diodes
Samuel, Prof Ifor - idws@st-andrews.ac.uk
Visible light emission can be stimulated by applying a voltage to a thin layer of an organic semiconductor. The light emitted provides a window on the physics of the material, enabling us to learn about the nature of the excited states in the material. It is also useful for information display, lighting, and even for the treatment of skin cancer. We have developed a new class of light-emitting organic semiconductor, which could be used for high efficiency lighting, thereby reducing energy consumption.
Visible light emission can be stimulated by applying a voltage to a thin layer of an organic semiconductor. The light emitted provides a window on the physics of the material, enabling us to learn about the nature of the excited states in the material. It is also useful for information display, lighting, and even for the treatment of skin cancer. We have developed a new class of light-emitting organic semiconductor, which could be used for high efficiency lighting, thereby reducing energy consumption.
Organic Solar Cells
Samuel, Prof Ifor - idws@st-andrews.ac.uk
The energy crisis is probably the most important problem facing the world today. Sunlight is the most abundant renewable energy source, but at present the cost of photovoltaics is too high for solar cells to be a serious alternative to fossil fuels. Organic semiconductors offer the prospect of low cost solar cells, but their efficiency needs improvement. We are working on new measurements to understand organic solar cell operation, and new materials to improve it.
The energy crisis is probably the most important problem facing the world today. Sunlight is the most abundant renewable energy source, but at present the cost of photovoltaics is too high for solar cells to be a serious alternative to fossil fuels. Organic semiconductors offer the prospect of low cost solar cells, but their efficiency needs improvement. We are working on new measurements to understand organic solar cell operation, and new materials to improve it.
Plastic Lasers
Turnbull, Dr Graham - gat@st-andrews.ac.uk
Conjugated polymers are a very special class of plastics that are both semiconducting and efficient light-emitters. They have been widely applied as flat and flexible light emitting displays, as well as visible lasers, optical amplifiers, solar cells and electronic circuits. As novel laser media, polymers are particularly attractive because they can be easily and inexpensively formed into flexible shapes and structures that are inaccessible to crystalline materials.
This project builds on our internationally recognised research programme in polymer lasers. We have demonstrated plastic lasers driven by a light-emitting diode and are currently developing lasers and optical amplifiers integrated with nitride LEDs and CMOS control electronics. Novel photonic nanostructures are used to control
laser emission, develop new modes of operation and applications in sensing and datacomms.
Conjugated polymers are a very special class of plastics that are both semiconducting and efficient light-emitters. They have been widely applied as flat and flexible light emitting displays, as well as visible lasers, optical amplifiers, solar cells and electronic circuits. As novel laser media, polymers are particularly attractive because they can be easily and inexpensively formed into flexible shapes and structures that are inaccessible to crystalline materials.
This project builds on our internationally recognised research programme in polymer lasers. We have demonstrated plastic lasers driven by a light-emitting diode and are currently developing lasers and optical amplifiers integrated with nitride LEDs and CMOS control electronics. Novel photonic nanostructures are used to control
laser emission, develop new modes of operation and applications in sensing and datacomms.
Plastic nano-photonics
Turnbull, Dr Graham - gat@st-andrews.ac.uk
Conjugated polymers are a very special class of plastics that are both semiconducting and efficient light-emitters. They have been widely applied as flat and flexible light emitting displays, visible lasers, and solar cells.
For photonics applications, polymers are particularly attractive because they can be easily and inexpensively formed into flexible shapes and structures. Simple processing such as nanoimprint lithography and electrospinning has enabled polymer microlasers with unorthodox resonators and for nanostructured OLEDs for enhanced efficiency.
This project will explore novel nanostructures for controlling light emission and absorption in thin polymer films and fibres. Nanoimprint lithography and electrospinning will be used to fabricate photonic nanostructures in polymer waveguides and microcavities. Potential applications include nano light sources, optical concentrators, sensors, solar power and displays.
Conjugated polymers are a very special class of plastics that are both semiconducting and efficient light-emitters. They have been widely applied as flat and flexible light emitting displays, visible lasers, and solar cells.
For photonics applications, polymers are particularly attractive because they can be easily and inexpensively formed into flexible shapes and structures. Simple processing such as nanoimprint lithography and electrospinning has enabled polymer microlasers with unorthodox resonators and for nanostructured OLEDs for enhanced efficiency.
This project will explore novel nanostructures for controlling light emission and absorption in thin polymer films and fibres. Nanoimprint lithography and electrospinning will be used to fabricate photonic nanostructures in polymer waveguides and microcavities. Potential applications include nano light sources, optical concentrators, sensors, solar power and displays.
Silicon - the ideal photonic material at longer wavelength
Krauss, Prof Thomas - tfk@st-andrews.ac.uk
Silicon is the material of choice for the microelectronics industry, but its use in Photonics is limited by effects such as two-photon absorption and the resulting free-carrier absorption. At wavelengths above 2.2 µm, however, these limitations no longer apply, and silicon exhibits some of the most favourable properties of any photonic material. The aim of this project is to explore the potential of silicon in this wavelength regime, especially with respect to resonantly enhanced functionality as occurs in slow light waveguides and cavities. Examples include the following:
1. - Enhanced nonlinear effects in cavities and slow light waveguides. We have already observed many exciting nonlinear effects in silicon in the near-IR wavelength regime (Overview: T. F. Krauss, "Why do we need slow light?," Nature Photonics, 2 (8), 448-450 (2008); Third harmonic: B. Corcoran, C. Monat, C. Grillet, D. J. Moss, B. J. Eggleton, T. P. White, L. O'Faolain, T. F. Krauss, "Green light emission in silicon through slow-light enhanced third-harmonic generation in photonic-crystal waveguides," Nature Photonics, 3 (4), 206-210 (2009); and M. Galli, D. Gerace, K. Welna, T. F. Krauss, L. O'Faolain, G. Guizzetti, L. C. Andreani, "Low-power continuous-wave generation of visible harmonics in silicon photonic crystal nanocavities," Optics Express, 18 (25), 26613-26624 (2010); Four wave mixing: J. Li, L. O'Faolain, I. H. Rey, T. F. Krauss, "Four-wave mixing in photonic crystal waveguides: slow light enhancement and limitations," Optics Express, 19 (5), 4458-4463 (2011)). These effects will be orders of magnitude stronger in the MID-IR, thus opening a truly novel realm of all-optical signal processing.
2. - Emission control. It may be possible to create novel light emitters with photonic-crystal controlled emission, thus providing novel and versatile sources.
3. - Sensing and filtering. Gas sensing and related environmental sensing is one of the most important applications for MID-IR photonics. Using the exquisite filtering properties of photonic crystal lattices and cavities, advanced sensing functionalities can be realised.
The project will be based in the Microphotonics Group at St Andrews University (www.st-andrews.ac.uk/microphotonics) and will involve the design, fabrication and characterisation of waveguides, cavities and devices with the above fundamental and applied functionalities in mind. Some of the work will be carried out in the departmental cleanroom and the student will become proficient in all of the relevant technologies, including electron-beam lithography, dry etching and thin film deposition. The structures will be characterised with a tunable Optical Parametric Oscillator operating in the 2.5-3.4 µm range.
Silicon is the material of choice for the microelectronics industry, but its use in Photonics is limited by effects such as two-photon absorption and the resulting free-carrier absorption. At wavelengths above 2.2 µm, however, these limitations no longer apply, and silicon exhibits some of the most favourable properties of any photonic material. The aim of this project is to explore the potential of silicon in this wavelength regime, especially with respect to resonantly enhanced functionality as occurs in slow light waveguides and cavities. Examples include the following:
1. - Enhanced nonlinear effects in cavities and slow light waveguides. We have already observed many exciting nonlinear effects in silicon in the near-IR wavelength regime (Overview: T. F. Krauss, "Why do we need slow light?," Nature Photonics, 2 (8), 448-450 (2008); Third harmonic: B. Corcoran, C. Monat, C. Grillet, D. J. Moss, B. J. Eggleton, T. P. White, L. O'Faolain, T. F. Krauss, "Green light emission in silicon through slow-light enhanced third-harmonic generation in photonic-crystal waveguides," Nature Photonics, 3 (4), 206-210 (2009); and M. Galli, D. Gerace, K. Welna, T. F. Krauss, L. O'Faolain, G. Guizzetti, L. C. Andreani, "Low-power continuous-wave generation of visible harmonics in silicon photonic crystal nanocavities," Optics Express, 18 (25), 26613-26624 (2010); Four wave mixing: J. Li, L. O'Faolain, I. H. Rey, T. F. Krauss, "Four-wave mixing in photonic crystal waveguides: slow light enhancement and limitations," Optics Express, 19 (5), 4458-4463 (2011)). These effects will be orders of magnitude stronger in the MID-IR, thus opening a truly novel realm of all-optical signal processing.
2. - Emission control. It may be possible to create novel light emitters with photonic-crystal controlled emission, thus providing novel and versatile sources.
3. - Sensing and filtering. Gas sensing and related environmental sensing is one of the most important applications for MID-IR photonics. Using the exquisite filtering properties of photonic crystal lattices and cavities, advanced sensing functionalities can be realised.
The project will be based in the Microphotonics Group at St Andrews University (www.st-andrews.ac.uk/microphotonics) and will involve the design, fabrication and characterisation of waveguides, cavities and devices with the above fundamental and applied functionalities in mind. Some of the work will be carried out in the departmental cleanroom and the student will become proficient in all of the relevant technologies, including electron-beam lithography, dry etching and thin film deposition. The structures will be characterised with a tunable Optical Parametric Oscillator operating in the 2.5-3.4 µm range.
Silicon light emission in photonic crystal nanocavities
Krauss, Prof Thomas - tfk@st-andrews.ac.uk
Due to its indirect bandgap, silicon is an intrinsically poor light emitter. Surprisingly, a combination of material treatment and enhanced light-matter interaction in photonic crystal cavities does offer interesting opportunities for providing laser-like light sources. Having already demonstrated some of the highest Q-factor cavities and lowest loss waveguides in silicon, we have recently observed suprisingly efficient photoluminescence and elelctroluminescence from silicon nanocavities (R. Lo Savio, S. L. Portalupi, D. Gerace, A. Shakoor, T. F. Krauss, L. O'Faolain, L. C. Andreani, M. Galli, "Room-temperature emission at telecom wavelengths from silicon photonic crystal nanocavities," Appl. Phys. Lett., 98 (20), 201106 (2011)). The resulting spectral and spatial density of emission in terms of power per unit area and wavelength is amongst the most efficient silicon light emitters ever realised, and is beginning to approach that of III-V materials.
The project involves working with materials scientists in order to understand the luminescence process better, which is based on Hydrogen incorporation into the silicon lattice. In addition, you will design novel tpyes of cavities and coupled cavity structures that further enhance the radiation effiiciency, with the goal of achieving laser emission in due course. If successful, this project will introduce silicon as a viable light emitting material and transform the field of Photonics.
The project will be based in the Microphotonics Group at St Andrews University (www.st-andrews.ac.uk/microphotonics) and will involve the design, fabrication and characterisation of cavities and devices designed to maximise lighrt-mastter interaction and light emission. Some of the work will be carried out in the departmental cleanroom and the student will become proficient in all of the relevant technologies, including electron-beam lithography, dry etching and thin film deposition.
Due to its indirect bandgap, silicon is an intrinsically poor light emitter. Surprisingly, a combination of material treatment and enhanced light-matter interaction in photonic crystal cavities does offer interesting opportunities for providing laser-like light sources. Having already demonstrated some of the highest Q-factor cavities and lowest loss waveguides in silicon, we have recently observed suprisingly efficient photoluminescence and elelctroluminescence from silicon nanocavities (R. Lo Savio, S. L. Portalupi, D. Gerace, A. Shakoor, T. F. Krauss, L. O'Faolain, L. C. Andreani, M. Galli, "Room-temperature emission at telecom wavelengths from silicon photonic crystal nanocavities," Appl. Phys. Lett., 98 (20), 201106 (2011)). The resulting spectral and spatial density of emission in terms of power per unit area and wavelength is amongst the most efficient silicon light emitters ever realised, and is beginning to approach that of III-V materials.
The project involves working with materials scientists in order to understand the luminescence process better, which is based on Hydrogen incorporation into the silicon lattice. In addition, you will design novel tpyes of cavities and coupled cavity structures that further enhance the radiation effiiciency, with the goal of achieving laser emission in due course. If successful, this project will introduce silicon as a viable light emitting material and transform the field of Photonics.
The project will be based in the Microphotonics Group at St Andrews University (www.st-andrews.ac.uk/microphotonics) and will involve the design, fabrication and characterisation of cavities and devices designed to maximise lighrt-mastter interaction and light emission. Some of the work will be carried out in the departmental cleanroom and the student will become proficient in all of the relevant technologies, including electron-beam lithography, dry etching and thin film deposition.
Single-molecule Fluorescence Microscopy
Penedo-Esteiro, Dr Carlos - jcp10@st-andrews.ac.uk
Samuel, Prof Ifor - idws@st-andrews.ac.uk
In only a few years since its first observation, single-molecule fluorescence microscopy has evolved to a new frontier in science, with high impact and potential for a wide range of disciplines, such as material research, analytical chemistry and biological sciences. The possibility of tracking the motion and behaviour of individual molecules as they are excited by a laser beam has become a powerful tool that is revolutionising our knowledge about how proteins and other biomolecules work. On the other hand, DNA repair is a cellular mechanism to correct damage to DNA before it can become fixed as a mutation or chromosomal aberration. Therefore, understanding the molecular mechanism of DNA damage and repair is important for reducing the risk of cancer, as well as developing more effective cancer therapies. In this project we want to apply state-of-the-art single-molecule fluorescence techniques to study the Nucleotide Excision Repair (NER) pathway. Defects in NER are associated with three inherited human diseases – Xeroderma Pigmentosum (XP), Trichothipdystrophy (TTD) and Cockayne Syndrome (CS) – all of which have severe clinical consequences. This project is a collaboration between the School of Physics and Astronomy and the Biomolecular Science Centre at St Andrews and will provide the student with a strong expertise in the application of cutting-edge microscopy techniques to very important biological problems.
Further details at: http://www. st-andrews.ac.uk/~polyopto/
Samuel, Prof Ifor - idws@st-andrews.ac.uk
In only a few years since its first observation, single-molecule fluorescence microscopy has evolved to a new frontier in science, with high impact and potential for a wide range of disciplines, such as material research, analytical chemistry and biological sciences. The possibility of tracking the motion and behaviour of individual molecules as they are excited by a laser beam has become a powerful tool that is revolutionising our knowledge about how proteins and other biomolecules work. On the other hand, DNA repair is a cellular mechanism to correct damage to DNA before it can become fixed as a mutation or chromosomal aberration. Therefore, understanding the molecular mechanism of DNA damage and repair is important for reducing the risk of cancer, as well as developing more effective cancer therapies. In this project we want to apply state-of-the-art single-molecule fluorescence techniques to study the Nucleotide Excision Repair (NER) pathway. Defects in NER are associated with three inherited human diseases – Xeroderma Pigmentosum (XP), Trichothipdystrophy (TTD) and Cockayne Syndrome (CS) – all of which have severe clinical consequences. This project is a collaboration between the School of Physics and Astronomy and the Biomolecular Science Centre at St Andrews and will provide the student with a strong expertise in the application of cutting-edge microscopy techniques to very important biological problems.
Further details at: http://www. st-andrews.ac.uk/~polyopto/
The development and control of ultrafast lasers
Brown, Dr Tom - ctab@st-andrews.ac.uk
Ultrafast lasers are a class of devices that emit pulses in the fs regime. These lasers are now used in a wide range of applications from eye surgery to materials processing. Many such devices are based on techniques that were developed in St Andrews about 20 years ago. There still remain significant challenges with these systems including reducing cost and complexity, accurately measuring and understanding the output from these lasers and providing mechanisms for remote operation. In this project you will be working with the ultrafast laser group developing new materials and technique. You would also be expected to work closely with applications users to ensure that sources are developed which solve real world problems.
Ultrafast lasers are a class of devices that emit pulses in the fs regime. These lasers are now used in a wide range of applications from eye surgery to materials processing. Many such devices are based on techniques that were developed in St Andrews about 20 years ago. There still remain significant challenges with these systems including reducing cost and complexity, accurately measuring and understanding the output from these lasers and providing mechanisms for remote operation. In this project you will be working with the ultrafast laser group developing new materials and technique. You would also be expected to work closely with applications users to ensure that sources are developed which solve real world problems.
The optical characterisation of tissue samples (in conjunction with Professor Simon Herrington, School of Medicine)
Brown, Dr Tom - ctab@st-andrews.ac.uk
The use of tissue samples underpins much working medical diagnosis. For example patients regularly undergo tests where tissue samples are taken and subsequently examined by a pathologist. In this project we seek to show that advanced techniques such as Raman spectroscopy may be used to provide additional support to the pathologist in making accurate diagnosis by examining the underlying biochemistry of the sample. A project in this area will involve working closely with our researchers in Raman spectroscopy as well as with clinical staff from the School of Medicine. Students will build and run advanced spectroscopy system and play an active role in the statistical analysis of their results.
The use of tissue samples underpins much working medical diagnosis. For example patients regularly undergo tests where tissue samples are taken and subsequently examined by a pathologist. In this project we seek to show that advanced techniques such as Raman spectroscopy may be used to provide additional support to the pathologist in making accurate diagnosis by examining the underlying biochemistry of the sample. A project in this area will involve working closely with our researchers in Raman spectroscopy as well as with clinical staff from the School of Medicine. Students will build and run advanced spectroscopy system and play an active role in the statistical analysis of their results.
The QuVis quantum mechanics visualization project
Kohnle, Dr Antje - ak81@st-andrews.ac.uk
The University of St Andrews QuVis project aims to enhance student conceptual understanding of quantum mechanics through the development of animations and visualizations based on outcomes of education research into student difficulties in quantum mechanics. Evaluation goes hand-in-hand with development, and has been used to optimize interface design and content. However, no work has been done on optimizing the format of the animations to enhance student engagement and learning.
This project will use education research literature and pilot studies to develop a number of animations each in different formats (e.g. including additional interactive elements such as questions or explanation levels). A multi-institutional study will then investigate the influence of animation format on student engagement and learning. Outcomes will be used to optimize the format of all animations.
The project will also include work to support curriculum reform in quantum mechanics. The traditional, historical approach to teaching quantum mechanics has been questioned in recent years in the light of changing applications of quantum physics and emerging fields such as quantum information theory. Several textbooks now start from simple two-level systems (such as photon polarization) and develop the theory using discrete systems. One limitation of such an approach is that it can appear more abstract and link less easily to previously encountered physics. This project will support the development of a revised quantum mechanics curriculum by developing animations and visualizations for such a curriculum.
The QuVis animations and visualizations: http://www.st-andrews.ac.uk/~qmanim
The University of St Andrews QuVis project aims to enhance student conceptual understanding of quantum mechanics through the development of animations and visualizations based on outcomes of education research into student difficulties in quantum mechanics. Evaluation goes hand-in-hand with development, and has been used to optimize interface design and content. However, no work has been done on optimizing the format of the animations to enhance student engagement and learning.
This project will use education research literature and pilot studies to develop a number of animations each in different formats (e.g. including additional interactive elements such as questions or explanation levels). A multi-institutional study will then investigate the influence of animation format on student engagement and learning. Outcomes will be used to optimize the format of all animations.
The project will also include work to support curriculum reform in quantum mechanics. The traditional, historical approach to teaching quantum mechanics has been questioned in recent years in the light of changing applications of quantum physics and emerging fields such as quantum information theory. Several textbooks now start from simple two-level systems (such as photon polarization) and develop the theory using discrete systems. One limitation of such an approach is that it can appear more abstract and link less easily to previously encountered physics. This project will support the development of a revised quantum mechanics curriculum by developing animations and visualizations for such a curriculum.
The QuVis animations and visualizations: http://www.st-andrews.ac.uk/~qmanim
Waveguide lasers
Brown, Dr Tom - ctab@st-andrews.ac.uk
Most solid-state lasers require bulky and complex cavities. In this project we will explore how, by using optical confinement within a gain medium laser performance can be greatly enhanced. In it’s simplest form this comprises a one-dimensional confinement, however we also wish to explore the operation of channel waveguide devices based on either micro-machined or femtosecond direct written structures. Ultimately with mirrors attached directly to the endfaces of such devices, fully monolithic cavities can be produced. The geometry of such devices also permits intriguing opportunities for innovative pumping designs ultimately allowing the generation of high power output. Our vision is to incorporate technologies that permit the generation of ultrashort pulses for these devices and show, with the help of our collaborators, a wide range of applications for these lasers.
Most solid-state lasers require bulky and complex cavities. In this project we will explore how, by using optical confinement within a gain medium laser performance can be greatly enhanced. In it’s simplest form this comprises a one-dimensional confinement, however we also wish to explore the operation of channel waveguide devices based on either micro-machined or femtosecond direct written structures. Ultimately with mirrors attached directly to the endfaces of such devices, fully monolithic cavities can be produced. The geometry of such devices also permits intriguing opportunities for innovative pumping designs ultimately allowing the generation of high power output. Our vision is to incorporate technologies that permit the generation of ultrashort pulses for these devices and show, with the help of our collaborators, a wide range of applications for these lasers.
