Speaker: Prof. David A. Keen (University of Oxford)
Title: Local complexity in (mostly) cubic crystals
Date: 6 December 2022
Place: Building 1, meeting room
Cubic crystals have always appealed to condensed matter physicists for their conceptual simplicity and structural richness. The first crystal structure to be determined by X-ray diffraction was cubic and they still play a key role in diffraction instrumentation today. But what happens when parts of the structure deviate from cubic symmetry at a local level? How can we determine this local complexity experimentally and – equally importantly – interpret our data in a crystallographically coherent manner? This is what this talk will explore. I will outline an analysis methodology based on neutron and X-ray diffraction and pair distribution function methods which can be used to extract local complexity signatures within long-ranged ordered crystals. The talk will include a number of examples including phase transitions in perovskites, simple ice structures and other disordered cubic-structured materials.