DFT Methods for Complex Magnetic Systems

This is a fully funded studentship under the "Facilitity Development" programme of the ISIS Spallation Neutron source at Harwell,

Complex magnetism is fundamental to the electronic structure of solid state. Magnetic materials are the functional component of many technologies in widespread use today and under development for tomorrow. Magnetism also plays a key role in fundamental condensed-matter physics systems, such as multiferroics, iron arsenide superconductors and spin-ice pyrochlores. "Interesting" materials have complex magnetic ground states, featuring spin spirals, antiferromagnetic and ferrimagnetic states, charge and spin density waves, and geometrically frustrated antiferromagnetism. The two predominent methods for the study of such systems are electronic structure simulation methods and magnetic neutron scattering.

The first goal of this project is to advance the state-of-the-art in methods for electronic structure modelling for complex magnetic systems. DFT and related electronic structure methods ought to be capable of modelling of magnetic groundstates, treating all possible states of different orderings, itinerant or localised moment, collinear or noncollinear on the same footing. But except for simple ferromagnets, the combinatorial growth in the numbers of possible ground states hampers and sometimes defeats attempts to simulate more complex systems.

This will be addressed by use of constrained, directed and random search methods to map the landscape of self-consistent solutions of the Kohn-Sham spin-density-functional theory equations. The main code development platform will be the CASTEP electronic structure and materials modelling code, used by over 100 UK and worldwide research groups. This project will build on recent CASTEP developments including non-collinear magnetism and the spin-orbit term in the Hamiltonian. 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.

The second part of project will be to apply the newly developed methods to simulate magnetic materials associated with the ISIS experimental user programme, working closely with ISIS scientists and users. The candidate will be expected to spend a minimum of 12 months based at the ISIS facility on the Harwell Campus in Oxfordshire.

The successful candidate should have a bachelor’s or masters level degree in physics, a strong education in condensed matter physics, quantum mechanics and electronic structure of solids as well as excellent computer programming skills

For further details, please contact Professor Keith Refson ([Email Address Removed]).