Ab initio studies of electron-phonon coupling to the electron self-energy in organic crystals*

Organic crystals combine properties of individual molecules and extended periodic systems. They garner much scientific interest due to their high charge carrier mobilities, and because their unique electronic and vibrational properties challenge our understanding of fundamental optoelectronic processes. In this work we use density functional perturbation theory to study the phonon-scattering lifetimes, as well as the temperature dependence of the band structure. We find that a self-consistent approach to the electron self-energy due to electron-phonon coupling yields qualitative differences compared to a conventional approach, and shows much better agreement with experimental results. We discuss efficient methods for self-consistency in organic crystals, and implications on calculating band gap renormalization and quasiparticle lifetimes of these systems.