Condensed matter contains unimaginably large numbers of electrons in close contact. At first sight, therefore, it is quite surprising that the quantum theory of solids, developed in the early part of the 20th century by Bloch and others based on the assumption of independent electrons, has been so successful. In the last few decades, however, research has uncovered an increasing number of materials whose properties evade description by independent-electron models. These ‘quantum materials’ display non-trivial and often spectacular phenomena that result either from collective electronic behaviour or from geometric properties of the electron states. In this talk I shall introduce the field of quantum materials and discuss two themes which are becoming increasingly important: ‘emergence’ and ‘topology’. I shall draw upon recent work on unconventional magnetic and superconducting materials, and describe how modern scattering techniques are making it possible to unpick complex ordered phases and identify exotic emergent quasiparticles.
ABOUT THE SPEAKER:
Andrew Boothroyd is Professor of Physics at Oxford University and Fellow of Oriel College, Oxford. His research exploits neutron and x-ray scattering techniques to explore a range of emergent electronic states found in quantum materials, including novel magnetic states and unconventional superconductivity. He has published over 220 papers, and won the Institute of Physics Superconductivity Group Prize in 2011. Andrew took undergraduate and graduate degrees at the University of Cambridge, completing his PhD in Physics at the Cavendish Laboratory in 1988. Immediately afterwards he joined the University of Warwick, first as a postdoctoral research associate and shortly afterwards as a University Lecturer. In 1991, he was appointed to a faculty position in Physics at Oxford University with a Tutorial Fellowship at Oriel College. In 2006 he was awarded the title of Professor of Physics. He has served as Head of Condensed Matter Physics at Oxford (2004–2008) and as vice-Provost of Oriel College (2011–2015).