Accurate all-electron $G_0W_0$ quasiparticle energies employing the full-potential augmented planewave method

TL;DR

This paper demonstrates how to achieve highly accurate all-electron $G_0W_0$ quasiparticle energies using the full-potential augmented planewave method, addressing discrepancies among different computational approaches.

Contribution

It introduces a systematic approach to optimize basis sets and local orbitals in the FLAPW method for reliable $G_0W_0$ calculations, and provides benchmark data for the community.

Findings

Good agreement between FLAPW and PAW methods for quasiparticle energies.

Basis-set quality significantly impacts $G_0W_0$ results.

Benchmark data established for future $G_0W_0$ studies.

Abstract

The $GW$ approach of many-body perturbation theory (MBPT) has become a common tool for calculating the electronic structure of materials. However, with increasing number of published results, discrepancies between the values obtained by different methods and codes become more and more apparent. For a test set of small- and wide-gap semiconductors, we demonstrate how to reach the numerically \emph{best} electronic structure within the framework of the full-potential linearized augmented planewave (FLAPW) method. We first evaluate the impact of local orbitals in the Kohn-Sham eigenvalue spectrum of the underlying starting point. The role of the basis-set quality is then further analyzed when calculating the $G_0W_0$ quasiparticle energies. Our results, computed with the \exciting{} code, are compared to those obtained using the projector-augmented planewave (PAW) formalism, finding overall, good agreement between both methods. We also provide data produced with a typical FLAPW basis set as a benchmark for other $G_0W_0$ implementations.