A Finite-field Approach for $GW$ Calculations Beyond the Random Phase Approximation

TL;DR

This paper introduces a finite-field method for calculating density response functions to perform advanced $GW$ calculations beyond the random phase approximation, applicable to molecules and solids with hybrid functionals.

Contribution

It presents a novel finite-field approach enabling efficient $G_0W_0$ and $G_0W_0 ext{ extGamma}_0$ calculations beyond RPA, with a scheme to improve quasiparticle energy convergence.

Findings

Effective for molecules and solids

Addresses slow convergence issues

Applicable with hybrid density functionals

Abstract

We describe a finite-field approach to compute density response functions, which allows for efficient $G_0W_0$ and $G_0W_0\Gamma_0$ calculations beyond the random phase approximation. The method is easily applicable to density functional calculations performed with hybrid functionals. We present results for the electronic properties of molecules and solids and we discuss a general scheme to overcome slow convergence of quasiparticle energies obtained from $G_0W_0\Gamma_0$ calculations, as a function of the basis set used to represent the dielectric matrix.