PhD projects
Projects available for PhD projects in our group are listed below. Please get in touch with Professor Amalia Coldea (amalia.coldea@physics.ox.ac.uk) for further details.
We welcome applications from enthusiastic students who are excited and challenged by understanding the rich novel physical phenomena displayed by novel quantum materials.
1. Developing electronic tunable devices of thin flakes of iron-based superconductors
This project is to explore electronic and topological behaviour of quasi-two dimensional devices based on thin flakes of highly crystalline superconducting iron-based chalcogenides as well as Dirac and Weyl semimetals. The project will involve device preparation and a suite of physical properties measurements to study their electronic properties using high magnetic field and low temperatures. The aim is to search for quantum phenomena as well as for signature of topological matter in these highly tunable quantum material devices. The project will be hosted by the recently funded Oxford Centre for Applied Superconductivity (CfAS) in the Department of Physics. The student will investigate the phase diagrams of novel superconducting thin flake devices under different extreme conditions of high magnetic field, strain and pressure. Experiments using advanced techniques for transport will be performed using high magnetic field facilities available in Oxford and elsewhere. A suitable candidate needs to have a good understanding of condensed matter physics and good computing skills as well the ability to work well in an experimental team.
2. Tuning electronic ground states and superconductivity of iron-based superconductors under extreme experimental conditions
Applied hydrostatic pressure is a unique tuning parameter to study the characteristics of a nematic quantum critical point in the absence of long-range magnetic order in a single material and to gives access to the electronic structure and correlations of new magnetic and structural phases. FeSe is an unique superconductor that show a nematic electronic phase in which absence of magnetism at ambient pressure. However, a magnetic phase is stabilized at high pressure and superconductivity is enhanced four-fold. By combining the chemical pressure with the hydrostatic pressure in the series FeSe1-xSx, it is possible to separate the nematic and magnetic phases. This project will aim to understand the evolution of the complex Fermi surfaces and electronic interactions across the nematic phase transitions using applied hydrostatic pressure in different iron-based superconductors. High magnetic field and low temperatures will be used to access directly the Fermi surface by detecting quantum oscillations in different ground states tuned by applied hydrostatic pressure. A suitable candidate needs to have a good understanding of condensed matter physics and good experimental and computational skills as well the ability to work well in an experimental team.
3. Revealing topological signatures in the electronic behaviour of bulk quantum materials with Dirac dispersion
This is an experimental project combining electronic transport and quantum oscillations to detect unusual signatures of the manifestation of topology in single crystals of quantum materials with Dirac dispersions. The student will perform a series of studies in high magnetic fields and at low temperatures to search for evidence of non-trivial Berry phases and low temperature quantum transport. Studies will be also extended under applied pressure and strain to identify proximity to new topological superconducting phase. The work will be combined with first-principle band structure calculations to compare with experiments and disentangle trivial from non-trivial effects. A suitable candidate needs to have a good understanding of condensed matter physics and good computing skills as well the ability to work well in an experimental team.
Details about the application process can be found here and concerning the available scholarships can be found here.