A self-consistent, nonperturbative first-principles method for computing electron-phonon spectral functions and charge conductivity, extending the one-shot Fan-Migdal (G0D0) self-energy so the spectral function is renormalized self-consistently rather than in a single perturbative shot. Students learn how self-consistency (the scGD0 scheme, analogous to scGW0 for electron-electron interactions) removes the divergent quasiparticle dispersions and unphysical spectra that plague one-shot methods, and how conductivity follows from the resulting spectral function via the Green-Kubo bubble approximation. It is demonstrated on monolayer InSe, where it reconciles computed spectra with ARPES.
Presents a self-consistent, nonperturbative first-principles theory and implementation (the scGD0 method) for computing electron-phonon spectral functions and charge conductivity in real materials. S…