Bridging the size gap between density-functional and many-body perturbation theory

TL;DR

This paper introduces an efficient method for calculating quasi-particle spectra of large systems using GW approximation and Wannier-like orbitals, significantly expanding the size range of feasible calculations.

Contribution

The authors develop a new approach that extends GW calculations to hundreds of atoms by optimizing the evaluation of the polarization propagator with Wannier-like orbitals.

Findings

Validated on benzene and silicon with accurate results.

Successfully applied to vitreous silica and tetraphenylporphyrin.

Achieved over tenfold increase in system size capability.

Abstract

The calculation of quasi-particle spectra based on the GW approximation is extended to systems of hundreds of atoms, thus expanding the size range of current approaches by more than one order of magnitude. This is achieved through an optimal strategy, based on the use of Wannier-like orbitals, for evaluating the polarization propagator. Our method is validated by calculating the vertical ionization energies of the benzene molecule and the band structure of crystalline silicon. Its potentials are then demonstrated by addressing the quasi-particle spectrum of a model structure of vitreous silica, as well as of the tetraphenylporphyrin molecule.