Electronic and Optical Excitations in van der Waals Materials from a Non-Empirical Wannier-Localized Optimally-Tuned Screened Range-Separated Hybrid Functional

TL;DR

This paper introduces a non-empirical, transferable WOT-SRSH functional for accurately predicting electronic and optical properties of van der Waals materials, matching experimental and MBPT results.

Contribution

The authors develop a non-empirical WOT-SRSH method for vdW materials with transferable parameters, improving predictive accuracy for electronic and optical excitations.

Findings

Achieves accuracy comparable to experiments and MBPT.

Transferable parameters between monolayer and bulk.

Effective as a starting point for MBPT calculations.

Abstract

Accurate prediction of electronic and optical excitations in van der Waals (vdW) materials is a long-standing challenge for density functional theory. The recently proposed Wannier-localized optimally-tuned screened range-separated hybrid (WOT-SRSH) functional has proven successful in non-empirical determination of electronic band gaps and optical absorption spectra for various covalent and ionic crystals. However, for vdW materials the tuning of the material- and structure-dependent functional parameters has, until now, only been attained semi-empirically. Here, we present a non-empirical WOT-SRSH approach applicable to vdW materials, with the optimal functional parameters transferable between monolayer and bulk. We apply this methodology to prototypical vdW materials: black phosphorus, molybdenum disulfide, and hexagonal boron nitride (in the latter case including zero-point renormalization). We show that the WOT-SRSH approach consistently achieves accuracy levels comparable to experiments and ab initio many-body perturbation theory (MBPT) calculations for band structures and optical absorption spectra, both on its own and as an optimal starting point for MBPT calculations.