Maximally-localized Wannier functions for GW quasiparticles

TL;DR

This paper discusses the use of maximally-localized Wannier functions derived from GW quasiparticle calculations to accurately interpolate and analyze many-body band structures, demonstrating minimal differences from density-functional results.

Contribution

It introduces a method to generate Wannier functions from GW quasiparticles and shows their effectiveness in band structure interpolation with minimal differences from DFT.

Findings

Wannier functions can accurately interpolate GW band structures.

The method is efficient and works well for complex materials.

Differences between DFT and GW Wannier functions are minimal in studied cases.

Abstract

We review the formalisms of the self-consistent GW approximation to many-body perturbation theory and of the generation of optimally-localized Wannier functions from groups of energy bands. We show that the quasiparticle Bloch wave functions from such GW calculations can be used within this Wannier framework. These Wannier functions can be used to interpolate the many-body band structure from the coarse mesh of Brillouin zone points on which it is known from the initial calculation to the usual symmetry lines, and we demonstrate that this procedure is accurate and efficient for the self-consistent GW band structure. The resemblance of these Wannier functions to the bond orbitals discussed in the chemical community led us to expect differences between density-functional and many-body functions that could be qualitatively interpreted. However, the differences proved to be minimal in the cases studied. Detailed results are presented for SrTiO_3 and solid argon.