Electron-phonon scattering rates in complex polar crystals

The thermalization of fast electrons by phonons is studied in CsI, NaI, ${\mathrm{SrI}}_{2}$, and ${\mathrm{YAlO}}_{3}$. This numerical study uses an improvement to a recently developed method based on a density functional perturbation description of the phonon modes that provides a way to go beyond widely used phonon models based on binary crystals. The method is compared to standard ab initio approaches to the electron-phonon interaction. Improvements to this method are described, and scattering rates are presented and discussed. The relative activity of the numerous phonon modes in materials with complicated structures is discussed, and a simple criterion for finding the modes that scatter strongly is presented.