Accurate approximations to the GW self-energy electron-phonon coupling gradients

摘要: The accuracy of the many-body perturbation theory GW formalism to calculate electron-phonon coupling matrix elements has been recently demonstrated in case a few important systems. However, related computational costs are high and thus represent strong limitations its widespread application. In present study, we explore two less demanding alternatives for calculation on level. Namely, test static Coulomb-hole plus screened-exchange (COHSEX) approximation further constant screening approach, where variations screened Coulomb potential W upon small changes atomic positions along vibrational eigenmodes neglected. We find this latter be most reliable, whereas COHSEX ansatz leads substantial errors. Our conclusions validated paradigmatic cases: diamond, graphene, C60 fullerene. These findings open way combining approach with efficient linear-response theories.