Combined first-principles calculations of electron-electron and electron-phonon self-energies in condensed systems

TL;DR

This paper introduces an efficient method to compute electron-electron and electron-phonon self-energies simultaneously at the $G_0W_0$ level, allowing accurate predictions of band gap renormalization and defect states in large systems.

Contribution

It generalizes a previous molecular method to condensed systems, enabling inclusion of non-adiabatic and temperature effects without extra computational cost.

Findings

Accurate $G_0W_0$ band structures are crucial for reliable zero point renormalization predictions.

The method accurately computes ZPR of defect states in diamond.

Non-adiabatic effects are essential for precise defect state energy calculations.

Abstract

We present a method to efficiently combine the computation of electron-electron and electron-phonon self-energies, which enables the evaluation of electron-phonon coupling at the $G_0W_0$ level of theory for systems with hundreds of atoms. In addition, our approach, which is a generalization of a method recently proposed for molecules [J. Chem. Theory Comput. 2018, 14, 6269-6275], enables the inclusion of non-adiabatic and temperature effects at no additional computational cost. We present results for diamond and defects in diamond and discuss the importance of numerically accurate $G_0W_0$ band structures to obtain robust predictions of zero point renormalization (ZPR) of band gaps, and of the inclusion of non-adiabatic effect to accurately compute the ZPR of defect states in the band gap.