Diffuse scattering: the crystallography of dynamics, defects, and disorder

Periodic order is the sine qua non of crystallography. Yet sometimes it is the departure from order that is crucial for material function. Proteins, frustrated magnets, photovoltaics, battery materials, high-temperature superconductors â€" there are many examples of important systems where disorder of one sort or another plays a pivotal role. Crystallographically, the signature of disorder is the existence of a diffuse component to the scattering function, usually orders of magnitude weaker than the conventional Bragg scattering. The advent of intense radiation sources, the development of revolutionary detector technologies, and the ready availability of high-performance computing have collectively transformed our ability to measure and interpret diffuse scattering from disordered crystals.

This course will cover the background necessary to measure and interpret diffuse scattering from disordered crystals. Its contents span the theory of diffraction and diffuse scattering, the practicalities of its measurement, and the many different approaches taken to its interpretation. The programme is loosely split into two strands â€" one with a focus on materials chemistry and physics and the other concerned mostly with protein dynamics. Collectively, the course will cover the various origins of diffuse scattering (e.g. dynamics, compositional/displacive disorder, magnetic disorder), and its form in both single-crystal and powder samples.