Electronic structure and optical properties of halide double perovskites from a Wannier-localized optimally-tuned screened range-separated hybrid functional

TL;DR

This paper demonstrates that the Wannier-localized optimally-tuned screened range-separated hybrid (WOT-SRSH) functional accurately predicts the electronic and optical properties of halide double perovskites, aligning well with experimental data and advancing computational methods in this field.

Contribution

The study applies WOT-SRSH to halide double perovskites, showing its effectiveness in predicting their fundamental gaps and optical spectra, and compares it with other methods and previous calculations.

Findings

WOT-SRSH accurately predicts fundamental and optical band gaps.

Results are consistent with spectroscopic measurements.

WOT-SRSH is a viable method for halide double perovskite properties.

Abstract

Halide double perovskites are a chemically-diverse and growing class of compound semiconductors that are promising for optoelectronic applications. However, the prediction of their fundamental gaps and optical properties with density functional theory (DFT) and {\it ab initio} many-body perturbation theory has been a significant challenge. Recently, a nonempirical Wannier-localized optimally-tuned screened range-separated hybrid (WOT-SRSH) functional has been shown to accurately produce the fundamental band gaps of a wide set of semiconductors and insulators, including lead halide perovskites. Here we apply the WOT-SRSH functional to five halide double perovskites, and compare the results with those obtained from other known functionals and previous $GW$ calculations. We also use the approach as a starting point for $GW$ calculations and we compute the band structures and optical absorption spectrum for Cs\textsubscript{2}Ag{Bi}Br\textsubscript{6}, using both time-dependent DFT and the $GW$-Bethe-Salpeter equation approach. We show that the WOT-SRSH functional leads to accurate fundamental and optical band gaps, as well as optical absorption spectra, consistent with spectroscopic measurements, thereby establishing WOT-SRSH as a viable method for the accurate prediction of optoelectronic properties of halide double perovskites.