PhD Studentship: Excitations in antiferromagnets and altermagnets

Funding

EPSRC Doctoral Training Partnership Studentship offering the award of fees, together with a tax-free maintenance grant of £19,237 per year for 3.5 years.  Training and support will also be provided.

Lead Supervisor’s full name and email address

Dr Joseph Barker – [email protected]

Co-supervisor name(s)

Professor Christopher Marrows – [email protected]

Project summary

Magnetic materials contain quantised bosonic excitations called magnons, the magnetic equivalent of phonons. These govern the basic magnetic thermodynamics, but by artificially altering their population, similar to an electrical chemical potential, we can use magnons for transport. This enables circuits to be produced where information can flow even without electrical currents, so-called "spintronics".

The frontier of spintronics research is in antiferro- and alter-magnetic materials. These show no external magnetism, but inside are strongly ordered on an atomic level, with each magnetic atom exactly opposing its neighbours.

The advantage of using antiferromagnets or altermagnets is that they do not couple with external magnetic fields, nor do they produce external fields which would cause components to couple to each other. They also contain faster intrinsic dynamics, responding to changes at terahertz frequencies.

Currently, the magnon excitations in very few altermagnetic materials have been studied. Furthermore, most antiferromagnets were studied a long time ago before the concept of spintronics existed. The role of magnon chirality and topology is now a hot topic and we need to study materials with different internal symmetries to understand what physical effects are possible.

We have recently developed a method of using quantum statistics within atomic, dynamical spin models, opening a new era of quantitative modelling. This allows us to perform multiscale modelling where we work independently from experiments, starting from the basic principles of quantum mechanics using so-called ab initio methods and propagating information upwards in time and length scales. In this way we will make quantitative predictions about excitations in antiferromagnets and altermagnets truly independently of experiments.

Entry requirements plus any necessary or desired background

First or Upper Second Class UK Bachelor (Honours) degree or equivalent

Subject Area

Condensed Matter Physics