Two PhD studentships in first-principles materials simulation are offered at Royal Holloway, University of London. These are open to qualified applicants from the EU and EEA, and will remain open until filled.

DFT Methods for Complex magnetic Systems

This is a joint project with the ISIS spallation neutron source at the Rutherford Appleton Laboratory, Oxfordshire, with the aim of using and developing electronic structure calculation methods for the study of magnetism in advanced materials. Magnetic structure is fundamental to understanding the quantum solid state, and magnetic materials are the functional component of many present and future technologies. Examples such as multiferroics, high-temperature superconductors, thermoelectrics and spin-ice pyrochlores are at the cutting edge of condensed-matter physics research. Their magnetic ground states are frequently complex, featuring spin spirals, antiferromagnetic and ferrimagnetic order, charge and spin density waves, and geometrically frustrated antiferromagnetism. The first goal of this project is to advance the state-of-the-art in methods for DFT electronic structure modelling for complex magnetic systems, using random search methods to map the landscape of magnetic ground states. The main code development platform will be the CASTEP electronic structure and materials modelling code, used by over 100 UK and worldwide research groups. CASTEP is one of the most-used codes on UK national high-performance computing (HPC) facilitites including ARCHER and the project will be associated with the UK Car-Parrinello HPC consortium. There will also be collaborations with CASTEP developers and researchers at University College London, Oxford and York universities.

Computer modelling of half-Heusler alloys for thermoelectric waste heat recovery

Direct thermoelectric conversion via the Seebeck effect is set to play an increasing role in energy efficiency technology for waste heat recovery applications. Studies at the basic level of the relevant physical properties are essential to understand and improve the key active solid-state materials involved and discover new ones. This project will investigate a promising class of metal alloys with the half-Heusler structure, using advanced computer simulation methods based on density functional theory (DFT) simulations. These will primarily use the UK's leading DFT modelling code, CASTEP, and the national supercomputer, ARCHER. The successful candidate will receive training in state-of-the art DFT modelling methods, and will use these to investigate the phase diagrams, thermodynamic stability and vibrational dynamics (phonons). The project will be carried out as part of a collaboration with experimental groups who will perform experimental scanning tunneling electron microscopy (STEM) and inelastic neutron scattering (INS) studies. A key aspect of the project will be the use of DFT simulations to model and interpret the
experimental data. 

Among the important questions to be addressed is the effect of grain boundaries and interfaces on the phonon propagation, and consequent suppression of thermal conductivity, which is essential to obtain a high thermoelectric “figure of merit” ZT. This will require development of new modelling techniques for vibrational dynamics of non-crystalline phases. The project will also involve careful first principles thermodynamics studies of the phase stability of the solid solutions of TiNiSn and related alloys, and prediction of their properties when p- and n- doped. This project is associated with the EPSRC-funded collaborative grant EP/N01703X/1 (“Nanostructured half-Heuslers for thermoelectric waste heat recovery”) with project partners at Heriot-Watt andGlasgow universities,

For further details please contact Professor Keith Refson ([email protected]) and see

https://www.findaphd.com/search/ProjectDetails.aspx?PJID=60615&LID=964

and

https://www.findaphd.com/search/ProjectDetails.aspx?PJID=74035&LID=964