An Optimally-Tuned Starting Point for Single-Shot $GW$ Calculations of Solids

TL;DR

This paper demonstrates that using the WOT-SRSH functional as a starting point for single-shot GW calculations yields highly accurate band gaps for semiconductors and insulators, comparable to more complex methods.

Contribution

It introduces WOT-SRSH as an optimal initial eigensystem for $G_0W_0$ calculations, improving accuracy and reducing sensitivity to tuning ambiguities.

Findings

$G_0W_0$@WOT-SRSH achieves accuracy similar to QS$GW$ and ev$GW$.

Improves description of deeper valence states.

Reduces sensitivity of band gaps to tuning procedures.

Abstract

The dependence of ab initio many-body perturbation theory within the $GW$ approximation on the eigensystem used in calculating quasiparticle corrections limits this method's predictive power. Here, we investigate the accuracy of the recently developed Wannier-localized optimally tuned screened range-separated hybrid (WOT-SRSH) functional as a generalized Kohn-Sham starting point for single-shot $GW$ ($G_0W_0$) calculations for a range of semiconductors and insulators. Comparison to calculations based on well-established functionals, namely PBE, PBE0, and HSE, as well as to self-consistent $GW$ schemes and to experiment, shows that band gaps computed via $G_0W_0$@WOT-SRSH have a level of precision and accuracy that is comparable to that of more advanced methods such as quasiparticle self-consistent $GW$ (QS$GW$) and eigenvalue self-consistent $GW$ (ev$GW$). We also find that $G_0W_0$@WOT-SRSH improves the description of states deeper in the valence band manifold. Finally, we show that $G_0W_0$@WOT-SRSH significantly reduces the sensitivity of computed band gaps to ambiguities in the underlying WOT-SRSH tuning procedure.