Femtosecond electron diffuse scattering (FEDS) has emerged as a powerful technique to probe phonon dynamics in momentum space. FEDS data are rich in information, but are typically complex to interpret. A first important step in data analysis is to model accurately the thermal diffuse scattering background of materials. In this joint submission, we developed a first-principles methodology to fully address a fundamental process in solids, namely the phonon-induced inelastic scattering of x-rays, electrons, or neutrons. Besides obtaining excellent agreement between theory and experiment, we demonstrate that multi-phonon effects can drastically modify scattering signals for a large range of scattering wavevectors. The present method opens the way for large-scale high-throughput calculations, enabling the accurate interpretation of FEDS experiments.

Full publications: M. Zacharias et al. Phys. Rev. Lett. 127, 207401 (2021) and M. Zacharias et al. Phys. Rev. B 104, 205109 (2021)