Implementation of an all-electron GW approximation based on the PAW method without plasmon pole approximation: application to Si, SiC, AlAs, InAs, NaH and KH

TL;DR

This paper introduces a new all-electron GW approximation implementation using the PAW method without plasmon pole approximation, accurately computing quasiparticle energies for various materials and highlighting differences from pseudopotential methods.

Contribution

The paper presents a novel all-electron GW implementation based on PAW without plasmon pole approximation, enabling more accurate quasiparticle energy calculations.

Findings

Successfully computed quasiparticle energies for six materials.

Compared GWA results with other methods, showing significant differences.

Demonstrated the method's ability to compute frequency-dependent self-energy and spectral functions.

Abstract

A new implementation of the GW approximation (GWA) based on the all-electron Projector-Augmented-Wave method (PAW) is presented, where the screened Coulomb interaction is computed within the Random Phase Approximation (RPA) instead of the plasmon-pole model. Two different ways of computing the self-energy are reported. The method is used successfully to determine the quasiparticle energies of six semiconducting or insulating materials: Si, SiC, AlAs, InAs, NaH and KH. To illustrate the novelty of the method the real and imaginary part of the frequency-dependent self-energy together with the spectral function of silicon are computed. Finally, the GWA results are compared with other calculations, highlighting that all-electron GWA results can differ markedly from those based on pseudopotential approaches.