Speaker: Prof Andrew Boothroyd, Oxford University

Abstract: Over the past two decades, topology has become an increasingly valuable tool in condensed matter research, providing a radically different way of thinking about materials and enabling the prediction and discovery of exotic states with intriguing physical properties. Topological metals and semimetals exhibit exceptional transport behaviour due to the existence of low energy quasiparticles which resemble relativistic fermions. A particular interest is to identify materials in which the topology of the electrons can be controlled by magnetic order or magnetic fields.

In this talk, I will give a general introduction to the field of topological electronic bands and then discuss how magnetic structures can couple to electronic band topology, drawing examples from very recent studies on several intermetallic compounds, including candidates for Weyl semimetals and axion insulators. I especially wish to highlight the strengths of scattering experiments using advanced neutron and synchrotron radiation techniques for probing important aspects of the magnetic structures.

Biography: Andrew Boothroyd is a Professor of Physics in the Physics Department at Oxford University, and a Tutorial Fellow of Oriel College. Currently he is serving as Associate Head of Department.

After completing his undergraduate and graduate degrees at the University of Cambridge, Andrew joined the University of Warwick, first as a postdoc and then as a University Lecturer. In 1992, he moved to Oxford University where he has served as Head of Condensed Matter Physics, Associate Head of Department, and as Vice-Provost of Oriel College.

Andrew’s research exploits neutron and x-ray scattering methods to study quantum materials. These are crystalline solids whose electronic behaviour is dominated by quantum effects. Well known examples are superconductors and various types of magnetic materials, and recently a major new research activity has developed around materials called topological semimetals.

In 2011, Andrew received the Institute of Physics’ Brian Pippard Prize, and in 2017 he was recognised as an Outstanding Referee by the American Physical Society.