Electron-electron and electron-phonon correlation effects on the finite-temperature electronic and optical properties of zinc-blende GaN

We combine the effect of the electron-electron and electron-phonon interactions to study the electronic and optical properties of zb-GaN. We show that only by treating the two effects at the same time is it possible to obtain an unprecedented agreement of the zero-and finite-temperature electronic gaps and absorption spectra with the experimental results. Compared to the state-of-the-art results our calculations predict a large effect on the main absorption peak position and width as well as on the overall absorption line shape. These important modifications are traced back to the combined electron-phonon damping mechanism and nonuniform GW level corrections. Our results demonstrate the importance of treating on equal footing the electron and phonon mediated correlation effects to obtain an accurate description of the physical properties of group III nitrides.