Global St Andrews and Bonn Doctoral Scholarship - Physics

Project

Some of the most intriguing and technologically relevant materials discovered in recent decades—e.g. high-temperature superconductors and quantum magnets—behave in ways that defy our conventional understanding of matter. Their unusual properties arise from strong interactions between electrons, leading to phenomena like superconductivity, magnetism, and quantum phase transitions. Understanding these “quantum materials” is essential for fundamental science and future applications in energy-efficient electronics and quantum computing.

To unravel these complex behaviors, scanning tunneling microscopy (STM) is a uniquely powerful technique that images materials at the scale of individual atoms. By observing the interference patterns of electron waves scattered by defects (quasiparticle interference, QPI), we can experimentally extract how the energy of a particle depends on its wavelength (the so-called band structure) and thus construct a detailed map of how electrons move and interact. However, interpreting these interference patterns in complex quantum materials requires advanced theoretical modeling of correlation effects to be integrated into the band structure simulations, while current tools are limited to cases where the electrons behave independently.

This project will develop a computational framework that incorporates advanced many-body techniques (developed in Bonn) into calcQPI (a St. Andrews development), a state-of-the art software package for simulating QPI data (see Figure). This will provide an entirely new tool for understanding the rich physics of electron correlations in and out of equilibrium directly from the measured QPI patterns.

As the PhD student you will:

2. Learn and apply advanced many-body techniques for complex materials and learn the using the calcQPI package.
3. Apply this framework to QPI experiments in close collaboration with the experimental STM group at St. Andrews to quantitatively link theory and experiment. Representative strongly correlated materials include so-called heavy-fermion compounds and unconventional superconductors.

As a result, you will obtain unique skills ranging from modelling at the forefront of theoretical physics, interpreting advanced spectroscopic data to development of code using massive parallelization techniques. You will interact with scientists from a wide range of backgrounds and gain hands-on experience in theory-experiment collaboration.

The training and research path are structured around the complementary expertise of the two partner institutions:

• Andrews phase (1 year): The student will receive initial training in QPI theory, STM data analysis, and band structure modeling using density functional theory (DFT) using VASP. They will become proficient in using calcQPI and constructing realistic tight-binding models from DFT calculations.
• Bonn phase (1.5 years): Under the supervision of Kroha, the student will learn state-of-the- art methods for modeling correlated electron states, such as NCA, DMFT, and combined approaches. This will include computing frequency-dependent self-energies and modeling the spectral functions of correlated systems.
• Final phase back in Andrews (1 year): The student will integrate the many-body self-energy formalism into calcQPI and apply the resulting tool to experimental data. This will include developing strategies to simulate and interpret non-equilibrium QPI data as well as completing the thesis and preparing publication.

Innovative Features

• First direct integration of many-body correlation effects into QPI
• Enabling quantitative, theory-driven interpretation of STM data on correlated
• Laying the foundation for non-equilibrium QPI, a completely new area of research.

Impact

This work will advance our fundamental understanding of correlated electron behavior at the atomic scale, with potential implications for technologies such as quantum computing, spintronics, and novel superconductors. It will also establish a unique computational framework that can be shared with the broader research community.

The project will be managed jointly between the School of Physics and Astronomy at St Andrews and the Institute for Physics at Bonn. The student will be supervised by Prof. Dr. Peter Wahl (St Andrews) and Prof. Dr. Johann Kroha (Bonn).

Informal enquiries regarding this scholarship may be addressed to the co-supervisors:

Prof. Dr. Peter Wahl (gpw2@st-andrews.ac.uk)

Prof. Dr. Johann Kroha (jkroha@uni-bonn.de)

Value of award (per year)

The funding comprises a scholarship equivalent of a full-fees award and stipend for a period of up to 3.5 years. It is expected that the student will spend half of the scholarship term at the University of St Andrews and half at the University of Bonn:

• For the period spent at the University of St Andrews, the scholarships will comprise a full tuition fee award and an annual stipend paid at a rate set by the University of St Andrews. For 2025-2026, the stipend is £19,775 p.a., with an annual uplift published by the University each academic year.

• For the period spent at the University of Bonn, the scholarship will comprise a monthly maintenance grant of €1,800. The University of Bonn does not charge any tuition fees, but students must pay a so-called social contribution once per semester (currently €315 per semester).

Unless otherwise specified, the scholarships do not cover:

• Any continuation, extension, or resubmission period/fees.
• A research training grant or another equivalent award for research expenses.
• Support for travel, immigration, health insurance and related charges between the partner institutions.

Duration of award

Up to 3.5 years. The student will be expected to spend approximately half of the award term at the University of St Andrews and half at the University of Bonn. The successful candidate will be expected to have completed the doctorate degree by the end of the award term. The award term excludes the continuation period and any extension periods.

Additional criteria

Admission and scholarship criteria of both universities must be met.

For St Andrews, please refer to details of how to apply and of entry requirements here: https://www.st-andrews.ac.uk/study/apply/postgraduate/research/.

How to apply

Applications for the international PhD scholarship should be submitted by email to either of the co-supervisors, Prof. J. Kroha (jkroha@uni-bonn.de) or Prof. P. Wahl (gpw2@st-andrews.ac.uk). Please indicate in your application that you wish to be considered for this Global Doctoral Scholarship (Wahl and Kroha).  

Scholarship applications should include the following documents:

• CV including information about publications.
• Transcripts of most recent degrees.
• Information about thesis components for a Master degree (thesis mark, word count, weight/length in comparison to the degree overall).
• Statement of motivation and suitability as a candidate for the project (max 500 words)

Following a successful application for the scholarship, candidates will be invited to submit an application to both universities for admission into the program through normal routes upon award of the scholarship.

Applications should be submitted to either of the co-supervisors via email to:

Prof. Dr. Peter Wahl (gpw2@st-andrews.ac.uk) or

Prof. Dr. Johann Kroha (jkroha@uni-bonn.de).

Next steps

Successful scholarship applicants will be invited to apply for admission to both universities from April 2026, and then formal outcomes of the position will be made, subject to provision of full application details and materials for entry to the programme at the agreed entry point in 2026-2027.

Successful scholarship applicants must meet all relevant entry requirements for admission including any immigration requirements that may be in place. Please see the advice on applying for research degree programmes at St Andrews and the PhD application guidelines at Bonn.

Terms and conditions

Terms and conditions of scholarships for St Andrews can be found here: Awards general terms and conditions.

When will I know the outcome?

By mid-April 2026. Awards are subject to final signatures of contracts between the parties and successful admission to both institutions.