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.
PhD in Photonics
PhD in Condensed Matter
PhD in Astrophysics
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.
Determining the origins of galaxy bimodality using empirical Bayes methods
Wild, Dr Vivienne - vw8@st-andrews.ac.uk
How galaxies form and evolve is one of the outstanding questions of modern astrophysics. Large surveys are providing an increasingly detailed census of both local and distant galaxies. Considerable progress is being made on quantifying the changing demographics of the galaxy population over the majority of the age of the Universe. Massive numerical simulations have revealed the “hierarchical” nature of structure formation, in the dark matter at least, with small dark matter halos coalescing to form larger gravitationally bound systems. Such simulations have had good success in reproducing the spatial distribution of galaxies observed in large surveys. However, the complex array of physical processes that affect baryons within the dark matter halos, (e.g. gas heating and cooling, star formation, feedback, torques and drag) has so far prevented us from building a comprehensive understanding of how and why galaxies grow and change over time.
This project is about understanding the physical processes responsible for changing galaxies from the irregular balls of gas observed at high redshift, into the bimodal population of star-forming spirals and quiescent ellipticals seen around us today.
In the last decade a Bayesian approach to the fitting of sophisticated models to high quality spectra and/or multiwavelength photometry has become common place in the analysis of galaxies at all redshifts (see Walcher et al. 2011 for a review). The comparison of models and data is a complex, but well-studied statistical and mathematical problem, and the simple Bayesian techniques used in the field of galaxy evolution can be substantially improved upon.
Empirical, or hierarchical, Bayes techniques are starting to appear in the astronomical literature to solve problems as diverse as QSO redshift estimation (Bovy et al. 2011), exo-planet orbit analysis (Hogg et al. 2011) and the properties of SN 1a light curves (Mandel et al. 2009). They differ from standard Bayesian methods by fitting the entire dataset in a coherent manner, instead of single objects using pre-defined priors. For galaxy evolution studies, this will improve our ability to break degeneracies.
This project will analyse data from two surveys: GAMA and CALIFA. For more information on these surveys see there websites:
http://www.gama-survey.org/
http://www.caha.es/CALIFA/public_html/
This project is funded by the EU funded ERC starting grant held by Dr. Wild, is for a period of 3.5 years, and comes with substantial travel funds. The student will work within an active group of young and experienced researchers both within the University of St Andrews and around the world (UK, Australia, Germany, Spain, Finland).
The project involves the development of statistical techniques to make them applicable to astronomical datasets. Applications from students with a background in maths or physics and interest in astrophysics are welcome, as well as from students with a background in astrophysics but strong aptitude for maths and statistics.
For further information please see Dr. Wild's website or send her an email (http://www-star.st-and.ac.uk/~vw8/)
References:
Bovy J., Myers A. D., Hennawi J. F. et al. arXiv:1105.3975
Hogg D. W., Myers A. D., Bovy J., 2010, ApJ, 725, 2166
Mandel K. S.; Wood-Vasey W. M., Friedman A. S., Kirshner R. P., 2009, ApJ, 704, 629
Walcher C. J., Groves B., Budavri T., Dale D., Ap&SS, 2011, 331, 1
How galaxies form and evolve is one of the outstanding questions of modern astrophysics. Large surveys are providing an increasingly detailed census of both local and distant galaxies. Considerable progress is being made on quantifying the changing demographics of the galaxy population over the majority of the age of the Universe. Massive numerical simulations have revealed the “hierarchical” nature of structure formation, in the dark matter at least, with small dark matter halos coalescing to form larger gravitationally bound systems. Such simulations have had good success in reproducing the spatial distribution of galaxies observed in large surveys. However, the complex array of physical processes that affect baryons within the dark matter halos, (e.g. gas heating and cooling, star formation, feedback, torques and drag) has so far prevented us from building a comprehensive understanding of how and why galaxies grow and change over time.
This project is about understanding the physical processes responsible for changing galaxies from the irregular balls of gas observed at high redshift, into the bimodal population of star-forming spirals and quiescent ellipticals seen around us today.
In the last decade a Bayesian approach to the fitting of sophisticated models to high quality spectra and/or multiwavelength photometry has become common place in the analysis of galaxies at all redshifts (see Walcher et al. 2011 for a review). The comparison of models and data is a complex, but well-studied statistical and mathematical problem, and the simple Bayesian techniques used in the field of galaxy evolution can be substantially improved upon.
Empirical, or hierarchical, Bayes techniques are starting to appear in the astronomical literature to solve problems as diverse as QSO redshift estimation (Bovy et al. 2011), exo-planet orbit analysis (Hogg et al. 2011) and the properties of SN 1a light curves (Mandel et al. 2009). They differ from standard Bayesian methods by fitting the entire dataset in a coherent manner, instead of single objects using pre-defined priors. For galaxy evolution studies, this will improve our ability to break degeneracies.
This project will analyse data from two surveys: GAMA and CALIFA. For more information on these surveys see there websites:
http://www.gama-survey.org/
http://www.caha.es/CALIFA/public_html/
This project is funded by the EU funded ERC starting grant held by Dr. Wild, is for a period of 3.5 years, and comes with substantial travel funds. The student will work within an active group of young and experienced researchers both within the University of St Andrews and around the world (UK, Australia, Germany, Spain, Finland).
The project involves the development of statistical techniques to make them applicable to astronomical datasets. Applications from students with a background in maths or physics and interest in astrophysics are welcome, as well as from students with a background in astrophysics but strong aptitude for maths and statistics.
For further information please see Dr. Wild's website or send her an email (http://www-star.st-and.ac.uk/~vw8/)
References:
Bovy J., Myers A. D., Hennawi J. F. et al. arXiv:1105.3975
Hogg D. W., Myers A. D., Bovy J., 2010, ApJ, 725, 2166
Mandel K. S.; Wood-Vasey W. M., Friedman A. S., Kirshner R. P., 2009, ApJ, 704, 629
Walcher C. J., Groves B., Budavri T., Dale D., Ap&SS, 2011, 331, 1
Diffuse ionized gas in galaxies
Wood, Dr Kenny - 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.
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 Kenny - 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 Kenny - 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.
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 Kenny - 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. In particular, data from the high-resolution radio survey PEBBLES (an eMERLIN Key Project) will be used to measure grain growth and look for signs of rocks clumping together to make planetary cores, in the first few million years of stellar lifetimes.
Wood, Dr Kenny - 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. In particular, data from the high-resolution radio survey PEBBLES (an eMERLIN Key Project) will be used to measure grain growth and look for signs of rocks clumping together to make planetary cores, in the first few million years of stellar lifetimes.
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
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 98 planets confirmed by radial-velocity follow-up.
Possible components of a PhD project include:
- [New for 2013!] Developing new methods to use Gaia data products to improve the transit detection and pre-selection criteria for eliminating astrophysical and other false positives;
- Measuring stellar spin rates and spin-orbit misalignments using time-resolved spectroscopy during transits;
- Using high-resolution time-series transit spectroscopy to confirm the presence of planets around early-type stars;
- 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;
- Reconciling the planet catch with models of the galactic planet population and observational detection thresholds;
- Improving the quality of the SuperWASP photometry using image-subtraction and profile-fitting methods;
etc.
Specific project for Autumn 2013 intake:
=====================================
The hot gas giant planets found by ground-based surveys such as WASP and HAT represent a population that is statistically rare but extremely informative about formation and migration processes. Indeed they are so rare that they are not represented in the Kepler planet catch at all! With the imminent launch of the Gaia mission, I am keen to develop a student project to make use of the superb astrometric data that Gaia will provide, in order to add value to our existing and expanding databases. With reliable parallaxes, and with the ability to measure small astrometric shifts during transits, it will become very much easier to separate dwarfs from giants, and genuine planet candidates from hierarchical triples and other binary impostors. By combining databases in an intelligent way, I am confident that we will be able to reduce the false-positive rate dramatically. This is important, because we still need to at least double the number of ground-based planet discoveries in order to understand the importance of processes like Kozai migration and tidal orbit shrinkage. Our membership of the HARPS-North project will be invaluable for deepening our radial-velocity follow-up searches, and our partnership in the Las Cumbres network will also enable us to perform rapid and efficient photometric follow-up.
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 98 planets confirmed by radial-velocity follow-up.
Possible components of a PhD project include:
- [New for 2013!] Developing new methods to use Gaia data products to improve the transit detection and pre-selection criteria for eliminating astrophysical and other false positives;
- Measuring stellar spin rates and spin-orbit misalignments using time-resolved spectroscopy during transits;
- Using high-resolution time-series transit spectroscopy to confirm the presence of planets around early-type stars;
- 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;
- Reconciling the planet catch with models of the galactic planet population and observational detection thresholds;
- Improving the quality of the SuperWASP photometry using image-subtraction and profile-fitting methods;
etc.
Specific project for Autumn 2013 intake:
=====================================
The hot gas giant planets found by ground-based surveys such as WASP and HAT represent a population that is statistically rare but extremely informative about formation and migration processes. Indeed they are so rare that they are not represented in the Kepler planet catch at all! With the imminent launch of the Gaia mission, I am keen to develop a student project to make use of the superb astrometric data that Gaia will provide, in order to add value to our existing and expanding databases. With reliable parallaxes, and with the ability to measure small astrometric shifts during transits, it will become very much easier to separate dwarfs from giants, and genuine planet candidates from hierarchical triples and other binary impostors. By combining databases in an intelligent way, I am confident that we will be able to reduce the false-positive rate dramatically. This is important, because we still need to at least double the number of ground-based planet discoveries in order to understand the importance of processes like Kozai migration and tidal orbit shrinkage. Our membership of the HARPS-North project will be invaluable for deepening our radial-velocity follow-up searches, and our partnership in the Las Cumbres network will also enable us to perform rapid and efficient photometric follow-up.
Condensed Matter
Characterization of Triplet Superconductivity by Tunneling Spectroscopy
Wahl, Dr Peter - gpw2@st-andrews.ac.uk
In spin-triplet superconductors, cooper pairs are formed by electrons whose spins are aligned parallel. Examples of superconductors, where the electron pairing occurs with equal spins are Sr2RuO4 and some of the heavy fermion superconductors (e.g. ferromagnetic superconductors). In most of these materials, the superconducting order parameter and the properties of the superconducting state are only poorly understood. Part of the experimental challenge is that superconductivity typically only emerges at temperatures on the order of 1K. The properties of these superconductors are often intriguing and surprising, e.g. in ferromagnetic superconductors the material is at the same time magnetic and superconducting. Even without applied magnetic field, the superconductor can be expected to be in a vortex state due to the magnetization of the material itself.
During the first time of this project, the focus of your work will be to establish the sample preparation and to identify a triplet superconductor which is suitable for studies by spectroscopic imaging STM. In parallel, you will be trained to operate our spectroscopic imaging STM, which is mounted in a dilution refrigerator and can reach a base temperature of 7mK. The first part of this project will be carried out at the Max-Planck-Institute for Solid State Research, Stuttgart, Germany.
In spin-triplet superconductors, cooper pairs are formed by electrons whose spins are aligned parallel. Examples of superconductors, where the electron pairing occurs with equal spins are Sr2RuO4 and some of the heavy fermion superconductors (e.g. ferromagnetic superconductors). In most of these materials, the superconducting order parameter and the properties of the superconducting state are only poorly understood. Part of the experimental challenge is that superconductivity typically only emerges at temperatures on the order of 1K. The properties of these superconductors are often intriguing and surprising, e.g. in ferromagnetic superconductors the material is at the same time magnetic and superconducting. Even without applied magnetic field, the superconductor can be expected to be in a vortex state due to the magnetization of the material itself.
During the first time of this project, the focus of your work will be to establish the sample preparation and to identify a triplet superconductor which is suitable for studies by spectroscopic imaging STM. In parallel, you will be trained to operate our spectroscopic imaging STM, which is mounted in a dilution refrigerator and can reach a base temperature of 7mK. The first part of this project will be carried out at the Max-Planck-Institute for Solid State Research, Stuttgart, Germany.
Competing and Coexisting orders in Fe-based Superconductors
Wahl, Dr Peter - gpw2@st-andrews.ac.uk
The iron-based superconductors, an only recently discovered family of materials which become superconducting at temperatures up to ~50K, have almost all complex phase diagrams as a function of doping with structural and magnetic phase transitions. Superconductivity in these materials, similarly to high-temperature copper based superconductors, is most likely not mediated by phonon coupling, but rather either by some magnetically mediated coupling or due to electron correlations. In this regard, the importance of the magnetic and structural phases in these materials for superconductivity, and whether they coexist or compete with superconductivity become important questions. In this project, the aim is to determine the importance and possibly the origin of symmetry breaking electronic ordering for superconductivity. A nematic state in an iron-based superconductor has been first observed by STM in CaFe1.94Co0.06As2[1]. By spectroscopic imaging STM, you will attempt to search for ordering phenomena in the electronic excitations and study their dependence on temperature and magnetic field, in order to elucidate their relation to superconductivity. The first part of this project will be carried out at the Max-Planck-Institute for Solid State Research, Stuttgart, Germany.
T.-M. Chuang, M.P. Allan, J. Lee, Y. Xie, N. Ni, S.L. Bud’ko, G.S. Boebinger, P.C. Canfield, and J.C. Davis, Science 327, 181 (2010).
The iron-based superconductors, an only recently discovered family of materials which become superconducting at temperatures up to ~50K, have almost all complex phase diagrams as a function of doping with structural and magnetic phase transitions. Superconductivity in these materials, similarly to high-temperature copper based superconductors, is most likely not mediated by phonon coupling, but rather either by some magnetically mediated coupling or due to electron correlations. In this regard, the importance of the magnetic and structural phases in these materials for superconductivity, and whether they coexist or compete with superconductivity become important questions. In this project, the aim is to determine the importance and possibly the origin of symmetry breaking electronic ordering for superconductivity. A nematic state in an iron-based superconductor has been first observed by STM in CaFe1.94Co0.06As2[1]. By spectroscopic imaging STM, you will attempt to search for ordering phenomena in the electronic excitations and study their dependence on temperature and magnetic field, in order to elucidate their relation to superconductivity. The first part of this project will be carried out at the Max-Planck-Institute for Solid State Research, Stuttgart, Germany.
T.-M. Chuang, M.P. Allan, J. Lee, Y. Xie, N. Ni, S.L. Bud’ko, G.S. Boebinger, P.C. Canfield, and J.C. Davis, Science 327, 181 (2010).
Controllable topological phase transitions
King, Dr Phil - pdk6@st-andrews.ac.uk
Topological insulators are a fundamentally new form of quantum matter with striking properties, such as unusual spin-polarized metallic surface states. They are potential platforms to realize a range of fundamental and practical advances, including dissipationless transport and quantum computation. Controlling the transition between conventional band insulators and topological insulators is key to realizing their potential. Moreover, it is a rare example of a phase transition not characterized by symmetry breaking, the mainstay of condensed matter physics, but rather it is rooted in the mathematical concept of topology. In this project, you will explore new ways to exploit this in condensed matter systems. You will investigate methods to drive topological phase transitions, and study the interplay of topological order with additional phases such as superconductivity or magnetism. You will use angle-resolved photoemission spectroscopy (ARPES), a powerful probe of electronic structure, to track the evolution of the bulk band structure and the emergence of helical surface states. You will make extensive use of our state-of-the-art spectroscopy lab in St Andrews, and will also perform measurements at synchrotrons in the UK, Europe and the USA.
Topological insulators are a fundamentally new form of quantum matter with striking properties, such as unusual spin-polarized metallic surface states. They are potential platforms to realize a range of fundamental and practical advances, including dissipationless transport and quantum computation. Controlling the transition between conventional band insulators and topological insulators is key to realizing their potential. Moreover, it is a rare example of a phase transition not characterized by symmetry breaking, the mainstay of condensed matter physics, but rather it is rooted in the mathematical concept of topology. In this project, you will explore new ways to exploit this in condensed matter systems. You will investigate methods to drive topological phase transitions, and study the interplay of topological order with additional phases such as superconductivity or magnetism. You will use angle-resolved photoemission spectroscopy (ARPES), a powerful probe of electronic structure, to track the evolution of the bulk band structure and the emergence of helical surface states. You will make extensive use of our state-of-the-art spectroscopy lab in St Andrews, and will also perform measurements at synchrotrons in the UK, Europe and the USA.
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)
Holographic traps and guides for superfluidity studies and atom interferometry
Cassettari, Dr Donatella - dc43@st-andrews.ac.uk
Holographic traps are a new kind of optical traps for neutral atoms which are promising for a wide range of applications, e.g. quantum information processing and quantum simulation. They are produced by diffracting a laser beam off a computer-controlled optical device, known as a Spatial Light Modulator (SLM). This apparatus offers unparalleled flexibility in the choice of trapping geometry, and different experiments can be done simply by reconfiguring the SLM.
In this PhD project you will work on:
- Double well traps for confined atom interferometry, which is promising for the development of sensitive devices (see [1] for a review).
- Ring-shaped atom guides (see [2] and [3]), which can be used to observe superfluid motion of a Bose-Einstein condensate, e.g. persistent current states. BECs in these geometries and the study of their critical velocities (where superflow stops) have very important technological applications in sensing devices, such as superconducting quantum interference devices (SQUIDs). Moreover, theoretical proposals have been put forward in which coherent superposition of different BEC flows can be used as qubits.
[1] http://rmp.aps.org/abstract/RMP/v81/i3/p1051_1
[2] http://prl.aps.org/abstract/PRL/v106/i13/e130401
[3] http://lanl.arxiv.org/abs/1008.2140
Holographic traps are a new kind of optical traps for neutral atoms which are promising for a wide range of applications, e.g. quantum information processing and quantum simulation. They are produced by diffracting a laser beam off a computer-controlled optical device, known as a Spatial Light Modulator (SLM). This apparatus offers unparalleled flexibility in the choice of trapping geometry, and different experiments can be done simply by reconfiguring the SLM.
In this PhD project you will work on:
- Double well traps for confined atom interferometry, which is promising for the development of sensitive devices (see [1] for a review).
- Ring-shaped atom guides (see [2] and [3]), which can be used to observe superfluid motion of a Bose-Einstein condensate, e.g. persistent current states. BECs in these geometries and the study of their critical velocities (where superflow stops) have very important technological applications in sensing devices, such as superconducting quantum interference devices (SQUIDs). Moreover, theoretical proposals have been put forward in which coherent superposition of different BEC flows can be used as qubits.
[1] http://rmp.aps.org/abstract/RMP/v81/i3/p1051_1
[2] http://prl.aps.org/abstract/PRL/v106/i13/e130401
[3] http://lanl.arxiv.org/abs/1008.2140
Holographic traps for the efficient production of Bose-Einstein condensates
Cassettari, Dr Donatella - dc43@st-andrews.ac.uk
Evaporative cooling is an essential stage in the creation of Bose-Einstein condensates (BECs) in atomic gases. Recently we suggested [1] that holographic optical traps can be used to increase the evaporation efficiency, leading to larger BECs. In this PhD project you will implement this scheme, which will result in a simplified apparatus for the productions and subsequent manipulation of BECs.
[1] http://pra.aps.org/abstract/PRA/v84/i5/e053410
Evaporative cooling is an essential stage in the creation of Bose-Einstein condensates (BECs) in atomic gases. Recently we suggested [1] that holographic optical traps can be used to increase the evaporation efficiency, leading to larger BECs. In this PhD project you will implement this scheme, which will result in a simplified apparatus for the productions and subsequent manipulation of BECs.
[1] http://pra.aps.org/abstract/PRA/v84/i5/e053410
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 novel superconducting ground states in nanofabricated hybrid ferromagnetic-superconducting materials and devices using advanced neutron, muon and synchrotron techniques
Lee, Prof Steve - sl10@st-andrews.ac.uk
The search for novel quantum states of matter in artificial thin-film structures, in which superconducting (S) and ferromagnetic (F) materials are juxtaposed, has reached an exciting and timely stage of development. In the last year a series of new landmark experimental results seem set to herald a period of rapid expansion of interest and activity in the field. This was the pioneering observation by several groups of spin-triplet supercurrents traversing relatively thick F layers [1-3], believed theoretically to be signatures of a novel equal-spin spin-triplet and possibly ‘odd frequency’ superconducting state. This achievement represent the culmination of several years of breakthrough experiments [1-7] in a field whose modern era began almost most a decade ago, with the experimental discovery of Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) [8] type states in S-F-S structures [10]. What both the FFLO [8] and the odd-frequency pairing phenomena [9] have in common is that they were predicted to occur theoretically in bulk systems [8,9] but only in state-of-the-art artificial thin-film structures were they finally demonstrated to exist [1-7,10-13]. Modern thin-film growth and large area lithographic patterning open-up an enormous range of further possibilities for engendering novel quantum states of matter via the controlled interaction S and F order on the nanoscale. This capability also offers the promise of designing and engineering hybrid metamaterials (in a similar spirit to electromagnetic metamaterials) with tailored quantum properties. Concurrently there is enormous interest in spintronics, the manipulation of electronic spin for application in novel electronic devices. The structures investigated within this programme marry the fields of mesoscopic superconductivity, novel strongly correlated electron physics and spintronics. By introducing quantum coherence phenomena into spintronic types devices, this also opens up the possibility of non-locality and entanglement, with possible application long-term in quantum computation.
Professor Steve Lee leads an EPSRC funded Critical Mass Grant award (St Andrews, Leeds, Bath, Royal Holloway, ISIS, with partners in PSI ( Swizterland), Cambridge, and Leiden ) that underpins an international research programme that brings together a team with a wide range of relevant expertise to explore the physics of such systems. We make use of some of the most powerful probes in condensed matter physics (scattering and surface probe techniques) in order to throw new light onto the physics of artificial S-F metamaterials, with particular emphasis on spatially–resolved measurements. This combines with state-of-the-art facilities for materials growth and patterning and world leading instrumentation for measurement. The programme is also informed by cutting-edge theory. There are significant opportunities for research students within this collaboration, with excellent access to world leading research facilities (such as Diamond, ISIS, ILL, PSI, SLS). Due to the strong interactions between nodes there is also significant scope for student mobility in order to enhance training and experience. This is all underpinned by access to excellent graduate training bot via the SUPA Graduate School and the additional benefits of the Doctoral Training Centre in condensed matter physics based at St Andrews, Edinburgh and Heriot Watt.
[1] J.W.A. Robinson et al., Science 329 59 (2010).
[2] T.S. Khaire et al., PRL 104, 137002 (2010).
[3] M.S. Anwar et al., PRB 82, 100501 (2010).
[4] R.S. Keizer et al., Nature 439 825 (2006).
[5] J. Wang et al., Nat. Phys. 6 389 (2010).
[6] I. Sosnin et al., PRL 96 157002 (2006).
[7] D. Sprungmann et al., PRB 82, 060505 (2010).
[8] P. Fulde and R.A. Ferrell, PRB 135 A550 (1964);
A.I. Larkin and Y.N. Ovchinnikov, Zh. Eksp.
Teor. Fiz. 47, 1136 (1964).
[9] V.L. Berezinskii, JEPT Lett. 20, 287 (1974).
[10] V.V. Ryazanov et al., PRL 86, 2427 (2001); T. Kontos et al., PRL 89, 137007 (2002).
[11] A.I. Buzdin et al., JETP Letters 35, 178 (1982);
[12] F.S. Bergeret et al., PRL 86, 4096 (2001); Rev. Mod. Phys. 77, 1321 (2005).
[13] M. Eschrig et al., PRL 90, 137003 (2003); M. Eschrig and T. Löfwander, Nature Phys. 4 138 (2008).
The search for novel quantum states of matter in artificial thin-film structures, in which superconducting (S) and ferromagnetic (F) materials are juxtaposed, has reached an exciting and timely stage of development. In the last year a series of new landmark experimental results seem set to herald a period of rapid expansion of interest and activity in the field. This was the pioneering observation by several groups of spin-triplet supercurrents traversing relatively thick F layers [1-3], believed theoretically to be signatures of a novel equal-spin spin-triplet and possibly ‘odd frequency’ superconducting state. This achievement represent the culmination of several years of breakthrough experiments [1-7] in a field whose modern era began almost most a decade ago, with the experimental discovery of Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) [8] type states in S-F-S structures [10]. What both the FFLO [8] and the odd-frequency pairing phenomena [9] have in common is that they were predicted to occur theoretically in bulk systems [8,9] but only in state-of-the-art artificial thin-film structures were they finally demonstrated to exist [1-7,10-13]. Modern thin-film growth and large area lithographic patterning open-up an enormous range of further possibilities for engendering novel quantum states of matter via the controlled interaction S and F order on the nanoscale. This capability also offers the promise of designing and engineering hybrid metamaterials (in a similar spirit to electromagnetic metamaterials) with tailored quantum properties. Concurrently there is enormous interest in spintronics, the manipulation of electronic spin for application in novel electronic devices. The structures investigated within this programme marry the fields of mesoscopic superconductivity, novel strongly correlated electron physics and spintronics. By introducing quantum coherence phenomena into spintronic types devices, this also opens up the possibility of non-locality and entanglement, with possible application long-term in quantum computation.
Professor Steve Lee leads an EPSRC funded Critical Mass Grant award (St Andrews, Leeds, Bath, Royal Holloway, ISIS, with partners in PSI ( Swizterland), Cambridge, and Leiden ) that underpins an international research programme that brings together a team with a wide range of relevant expertise to explore the physics of such systems. We make use of some of the most powerful probes in condensed matter physics (scattering and surface probe techniques) in order to throw new light onto the physics of artificial S-F metamaterials, with particular emphasis on spatially–resolved measurements. This combines with state-of-the-art facilities for materials growth and patterning and world leading instrumentation for measurement. The programme is also informed by cutting-edge theory. There are significant opportunities for research students within this collaboration, with excellent access to world leading research facilities (such as Diamond, ISIS, ILL, PSI, SLS). Due to the strong interactions between nodes there is also significant scope for student mobility in order to enhance training and experience. This is all underpinned by access to excellent graduate training bot via the SUPA Graduate School and the additional benefits of the Doctoral Training Centre in condensed matter physics based at St Andrews, Edinburgh and Heriot Watt.
[1] J.W.A. Robinson et al., Science 329 59 (2010).
[2] T.S. Khaire et al., PRL 104, 137002 (2010).
[3] M.S. Anwar et al., PRB 82, 100501 (2010).
[4] R.S. Keizer et al., Nature 439 825 (2006).
[5] J. Wang et al., Nat. Phys. 6 389 (2010).
[6] I. Sosnin et al., PRL 96 157002 (2006).
[7] D. Sprungmann et al., PRB 82, 060505 (2010).
[8] P. Fulde and R.A. Ferrell, PRB 135 A550 (1964);
A.I. Larkin and Y.N. Ovchinnikov, Zh. Eksp.
Teor. Fiz. 47, 1136 (1964).
[9] V.L. Berezinskii, JEPT Lett. 20, 287 (1974).
[10] V.V. Ryazanov et al., PRL 86, 2427 (2001); T. Kontos et al., PRL 89, 137007 (2002).
[11] A.I. Buzdin et al., JETP Letters 35, 178 (1982);
[12] F.S. Bergeret et al., PRL 86, 4096 (2001); Rev. Mod. Phys. 77, 1321 (2005).
[13] M. Eschrig et al., PRL 90, 137003 (2003); M. Eschrig and T. Löfwander, Nature Phys. 4 138 (2008).
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.
(Jointly affiliated to both University of St Andrews and Max Planck Institute for the Chemical Physics of Solids, Dresden)
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.
(Jointly affiliated to both University of St Andrews and Max Planck Institute for the Chemical Physics of Solids, Dresden)
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.
Novel Quantum Order in Vector Magnetic Fields
Mackenzie, Prof Andy - apm9@st-andrews.ac.uk
Strongly interacting electron systems are one of the best hosts for study of the quantum many-body problem. Experimental discoveries made in the past decade show that, in the cleanest materials, a variety of subtle collective states form at low temperatures. Some of these are metallic but involve the development of a preferred direction, driven not by the crystal symmetry but by the electron-electron interactions themselves. To study anisotropic responses like these, careful experiments are necessary – they can easily be missed if the correct probes are not used. Many of the states discovered so far have a coupling to externally applied magnetic fields, so these fields can be used to ‘train’ the systems’ response functions. This has highlighted the need to develop better and better ‘vector magnets’ in which the field vector can be changed via computer-controlled energisation of multiple superconducting coils. On this project you will have access to world-leading instruments capable of generating 1, 1 and 9 tesla along the x, y and z axes. This will enable you to study transport and thermodynamic quantities that cannot be accessed in standard instruments. Using this unique instrumentation, you will have the chance to investigate a range of the most exciting new strongly correlated materials in a fast-moving field of modern research.
(Jointly affiliated to both University of St Andrews and Max Planck Institute for the Chemical Physics of Solids, Dresden)
Strongly interacting electron systems are one of the best hosts for study of the quantum many-body problem. Experimental discoveries made in the past decade show that, in the cleanest materials, a variety of subtle collective states form at low temperatures. Some of these are metallic but involve the development of a preferred direction, driven not by the crystal symmetry but by the electron-electron interactions themselves. To study anisotropic responses like these, careful experiments are necessary – they can easily be missed if the correct probes are not used. Many of the states discovered so far have a coupling to externally applied magnetic fields, so these fields can be used to ‘train’ the systems’ response functions. This has highlighted the need to develop better and better ‘vector magnets’ in which the field vector can be changed via computer-controlled energisation of multiple superconducting coils. On this project you will have access to world-leading instruments capable of generating 1, 1 and 9 tesla along the x, y and z axes. This will enable you to study transport and thermodynamic quantities that cannot be accessed in standard instruments. Using this unique instrumentation, you will have the chance to investigate a range of the most exciting new strongly correlated materials in a fast-moving field of modern research.
(Jointly affiliated to both University of St Andrews and Max Planck Institute for the Chemical Physics of Solids, Dresden)
Setup of a Combined STM/AFM for the Study of Layered Oxide Materials
Wahl, Dr Peter - gpw2@st-andrews.ac.uk
In this project, the setup of a new combined STM/AFM is envisioned. The study of correlated electron materials by spectroscopic imaging STM has become a valuable tool, especially to study excitations at low energies and in magnetic fields. Adding force detection has a number of advantages, besides obtaining an additional observable the force allows to independently define the tip-sample distance. The is particularly beneficial when studying poorly conducting or even insulating samples, such as e.g. oxide heterostructures, which are often capped by insulating layers.
Your part in this project will be to implement force detection in an existing STM head (for a description, see, e.g., Ref. 1) and make it work in a cryogenic environment. In parallel, the sample preparation to study layered oxide materials in STM will be established. The aim of the project is to investigate the properties of 2D electron gases at the interface in layered oxide heterostructures by tunneling spectroscopy. It has been shown in the past that in these heterostructures, electronic correlation effects can be taylored such that the interfacial electron gas becomes, e.g., superconducting or exhibits magnetic ordering [2]. Observation of the electronic states of the two-dimensional electron gas in tunneling spectroscopy would open the possibility to study the properties on the nanometer scale. The first part of this project will be carried out at the Max-Planck-Institute for Solid State Research, Stuttgart, Germany.
S.C. White, U.R. Singh and P. Wahl, A stiff STM head for measurement at low temperatures and in high magnetic fields, Rev. Sci. Instr. 82, 113708 (2011).
J. Mannhart and D. Schlom, Science 327, 1607 (2010).
In this project, the setup of a new combined STM/AFM is envisioned. The study of correlated electron materials by spectroscopic imaging STM has become a valuable tool, especially to study excitations at low energies and in magnetic fields. Adding force detection has a number of advantages, besides obtaining an additional observable the force allows to independently define the tip-sample distance. The is particularly beneficial when studying poorly conducting or even insulating samples, such as e.g. oxide heterostructures, which are often capped by insulating layers.
Your part in this project will be to implement force detection in an existing STM head (for a description, see, e.g., Ref. 1) and make it work in a cryogenic environment. In parallel, the sample preparation to study layered oxide materials in STM will be established. The aim of the project is to investigate the properties of 2D electron gases at the interface in layered oxide heterostructures by tunneling spectroscopy. It has been shown in the past that in these heterostructures, electronic correlation effects can be taylored such that the interfacial electron gas becomes, e.g., superconducting or exhibits magnetic ordering [2]. Observation of the electronic states of the two-dimensional electron gas in tunneling spectroscopy would open the possibility to study the properties on the nanometer scale. The first part of this project will be carried out at the Max-Planck-Institute for Solid State Research, Stuttgart, Germany.
S.C. White, U.R. Singh and P. Wahl, A stiff STM head for measurement at low temperatures and in high magnetic fields, Rev. Sci. Instr. 82, 113708 (2011).
J. Mannhart and D. Schlom, Science 327, 1607 (2010).
Spectroscopic studies of artificial quantum matter
King, Dr Phil - pdk6@st-andrews.ac.uk
Transition-metal oxides host a rich spectrum of properties such as high-temperature superconductivity, magnetism, and large responses to external stimuli, including colossal magnetoresistance and metal-insulator transitions. The ability to engineer such properties at will is an essential prerequisite for their use in advanced electronic applications, and would provide a unique playground for studying the quantum many-body problem. In this project, you will help to develop a novel system for the growth of custom oxide thin films by reactive molecular-beam epitaxy. This system will be coupled to a brand new angle-resolved photoemission (ARPES) facility at the UK synchrotron, Diamond Light Source, providing unprecedented opportunities to study the electronic structure and underlying many-body interactions of the films that you grow. You will tailor these properties using epitaxial strain, quantum confinement, and the creation of digital-oxide superlattices, with the ultimate goal to develop methodologies for the rational design of functional oxide materials.
This is an EPSRC CASE studentship offered in collaboration with Dr. Thorsten Hesjedal (Diamond Light Source & University of Oxford) and Dr. Moritz Hoesch (Diamond Light Source). You will spend extended periods developing and utilizing state-of-the-art facilities at the Rutherford Appleton Laboratory in Didcot, Oxfordshire, where Diamond is located.
Transition-metal oxides host a rich spectrum of properties such as high-temperature superconductivity, magnetism, and large responses to external stimuli, including colossal magnetoresistance and metal-insulator transitions. The ability to engineer such properties at will is an essential prerequisite for their use in advanced electronic applications, and would provide a unique playground for studying the quantum many-body problem. In this project, you will help to develop a novel system for the growth of custom oxide thin films by reactive molecular-beam epitaxy. This system will be coupled to a brand new angle-resolved photoemission (ARPES) facility at the UK synchrotron, Diamond Light Source, providing unprecedented opportunities to study the electronic structure and underlying many-body interactions of the films that you grow. You will tailor these properties using epitaxial strain, quantum confinement, and the creation of digital-oxide superlattices, with the ultimate goal to develop methodologies for the rational design of functional oxide materials.
This is an EPSRC CASE studentship offered in collaboration with Dr. Thorsten Hesjedal (Diamond Light Source & University of Oxford) and Dr. Moritz Hoesch (Diamond Light Source). You will spend extended periods developing and utilizing state-of-the-art facilities at the Rutherford Appleton Laboratory in Didcot, Oxfordshire, where Diamond is located.
Tailoring correlated solids through electrostatic surface control
King, Dr Phil - pdk6@st-andrews.ac.uk
Control of the source-drain conductivity of a semiconductor transistor by applying a small external voltage (so-called field-effect doping) underpins almost all current electronic devices. However, the transistor is widely accepted to be approaching its physical limits of performance. A new approach is required. In this project, you will investigate the potential of correlated electron materials – compounds where there are strong interactions between the constituent particles and which often exhibit emergent phases such as superconductivity and magnetism – for such applications. You will develop schemes to mimic field-effect doping in ultra-high vacuum while still leaving the sample surface accessible for advanced spectroscopic measurements. In particular, you will employ angle-resolved photoemission (ARPES) to simultaneously uncover how the electronic structure and many-body interactions evolve with such doping. ARPES measurements will be performed using our state-of-the-art system in St Andrews, as well as synchrotron light sources in the UK, Europe, and the USA.
Control of the source-drain conductivity of a semiconductor transistor by applying a small external voltage (so-called field-effect doping) underpins almost all current electronic devices. However, the transistor is widely accepted to be approaching its physical limits of performance. A new approach is required. In this project, you will investigate the potential of correlated electron materials – compounds where there are strong interactions between the constituent particles and which often exhibit emergent phases such as superconductivity and magnetism – for such applications. You will develop schemes to mimic field-effect doping in ultra-high vacuum while still leaving the sample surface accessible for advanced spectroscopic measurements. In particular, you will employ angle-resolved photoemission (ARPES) to simultaneously uncover how the electronic structure and many-body interactions evolve with such doping. ARPES measurements will be performed using our state-of-the-art system in St Andrews, as well as synchrotron light sources in the UK, Europe, and the USA.
Topological Superconductivity
Mackenzie, Prof Andy - apm9@st-andrews.ac.uk
The concepts of symmetry and symmetry breaking cut across all sub-fields of physics. Whether crystal symmetry in solids, gauge symmetry in superconductors or time reversal symmetry in ferromagnets, we have become used to defining phases of matter in terms of order parameters associated with symmetry breaking. However, not all collective quantum states can be fully characterised in terms of their symmetries. In some systems phases are classified in terms of their topological characteristics. Although this has been known for several decades, it was thought to apply in highly restricted circumstances. Exciting and rapid developments over the past five years have shown that these topologically characterised phases are likely to be much more widespread than first thought, and that, in the long term, it may be possible to exploit their properties in adventurous new technologies. Although progress has been rapid, fascinating theoretical questions remain, not least the interplay between symmetry and topology. The field is also ripe for experimental study. Superconductors are among the most fascinating candidates for topological systems. A host of intriguing theoretical proposals exist, but the extent to which they are observable in practice has yet to be determined. This project is concerned with investigating candidate topological superconductors, using a combination of the world-leading experimental facilities in St Andrews, Dresden and Cornell. The project is ambitious, and would be best suited to a candidate with both experimental and theoretical aptitude.
(Jointly affiliated to both University of St Andrews and Max Planck Institute for the Chemical Physics of Solids, Dresden)
The concepts of symmetry and symmetry breaking cut across all sub-fields of physics. Whether crystal symmetry in solids, gauge symmetry in superconductors or time reversal symmetry in ferromagnets, we have become used to defining phases of matter in terms of order parameters associated with symmetry breaking. However, not all collective quantum states can be fully characterised in terms of their symmetries. In some systems phases are classified in terms of their topological characteristics. Although this has been known for several decades, it was thought to apply in highly restricted circumstances. Exciting and rapid developments over the past five years have shown that these topologically characterised phases are likely to be much more widespread than first thought, and that, in the long term, it may be possible to exploit their properties in adventurous new technologies. Although progress has been rapid, fascinating theoretical questions remain, not least the interplay between symmetry and topology. The field is also ripe for experimental study. Superconductors are among the most fascinating candidates for topological systems. A host of intriguing theoretical proposals exist, but the extent to which they are observable in practice has yet to be determined. This project is concerned with investigating candidate topological superconductors, using a combination of the world-leading experimental facilities in St Andrews, Dresden and Cornell. The project is ambitious, and would be best suited to a candidate with both experimental and theoretical aptitude.
(Jointly affiliated to both University of St Andrews and Max Planck Institute for the Chemical Physics of Solids, Dresden)
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
Hybrid nanophotonics for visible light communications
Samuel, Prof Ifor - idws@st-andrews.ac.uk
Turnbull, Dr Graham - gat@st-andrews.ac.uk
Visible light communications is an emerging field that aims to deliver high-bandwidth wireless data through solid-state (LED) lighting. This project will be part of a new multi-disciplinary Programme Grant collaboration between the Universities of St Andrews, Strathclyde, Edinburgh, Oxford and Cambridge which will develop the next generation VLC technology.
The aim of this project will be to develop nanophotonic hybrid light sources and detectors based on luminescent polymer films. The student will design novel nanophotonic components, and fabricate these using nanoimprint lithography. Working with the partner universities, these components will be combined with gallium nitride LED arrays and CMOS electronics, for applications in visible light communications.
Turnbull, Dr Graham - gat@st-andrews.ac.uk
Visible light communications is an emerging field that aims to deliver high-bandwidth wireless data through solid-state (LED) lighting. This project will be part of a new multi-disciplinary Programme Grant collaboration between the Universities of St Andrews, Strathclyde, Edinburgh, Oxford and Cambridge which will develop the next generation VLC technology.
The aim of this project will be to develop nanophotonic hybrid light sources and detectors based on luminescent polymer films. The student will design novel nanophotonic components, and fabricate these using nanoimprint lithography. Working with the partner universities, these components will be combined with gallium nitride LED arrays and CMOS electronics, for applications in visible light communications.
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 Kenny - 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 Kenny - 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.
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.
Novel Lasers for Datacommunications
O'Faolain, Dr Liam - jww1@st-andrews.ac.uk
The large scale movement and storage of data has now become an essential component of the modern world. The emergence of Google, Facebook, Amazon and many others have changed the face of society and are now indispensable parts of everyday life. The Internet experience is now, somewhat invisibly, built around data centers, huge warehouses of computers. The power consumed by these is becoming very important (1% of US electricity consumption in 2005 [1]) with most of this power used to move data between computing cores. Optical interconnects are the solution to this problem offering dramatically higher bandwidths and low power consumption than the electrical equivalents.
The light source is the key component of an optical link. Not only must it be efficient, but it must also have a very controllable emission wavelength so as to enable Wavelength Division Multiplexing (WDM)- a key technique to maximise the available bandwidth. To date, this has not deployed for Datacommunications due to the lack of a suitable light source.
This project will develop new power efficient, narrow linewidth, tunable lasers based on novel highly efficient Photonic Crystal resonators and state-of-the-art semiconductor optical amplifiers.
[1] "Device Requirements for Optical Interconnects to Silicon Chips," Proceedings of the IEEE 97, 1166-1185 (2009)
The large scale movement and storage of data has now become an essential component of the modern world. The emergence of Google, Facebook, Amazon and many others have changed the face of society and are now indispensable parts of everyday life. The Internet experience is now, somewhat invisibly, built around data centers, huge warehouses of computers. The power consumed by these is becoming very important (1% of US electricity consumption in 2005 [1]) with most of this power used to move data between computing cores. Optical interconnects are the solution to this problem offering dramatically higher bandwidths and low power consumption than the electrical equivalents.
The light source is the key component of an optical link. Not only must it be efficient, but it must also have a very controllable emission wavelength so as to enable Wavelength Division Multiplexing (WDM)- a key technique to maximise the available bandwidth. To date, this has not deployed for Datacommunications due to the lack of a suitable light source.
This project will develop new power efficient, narrow linewidth, tunable lasers based on novel highly efficient Photonic Crystal resonators and state-of-the-art semiconductor optical amplifiers.
[1] "Device Requirements for Optical Interconnects to Silicon Chips," Proceedings of the IEEE 97, 1166-1185 (2009)
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 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
Samuel, Prof Ifor - idws@st-andrews.ac.uk
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.
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.
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.
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.
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.
