Advancing excited-state properties of two-dimensional materials using a dielectric-dependent hybrid functional

TL;DR

This paper introduces a dielectric-dependent hybrid functional tailored for 2D van der Waals materials, significantly improving the accuracy of electronic and optical property predictions while reducing computational costs compared to many-body methods.

Contribution

The authors develop a new SE-DD-RSH functional that accurately accounts for dielectric responses in 2D materials, enhancing predictive capabilities for band gaps and optical spectra.

Findings

Achieves accuracy comparable to G0 W0 and BSE@G0 W0 methods.

Improves band gap and optical absorption predictions for 2D materials.

Effective for heterostructures like MoS2/WS2.

Abstract

Predicting accurate band gaps and optical properties of lower-dimensional materials, including two-dimensional van der Waals (vdW) materials and their heterostructures, remains a challenge within density functional theory (DFT) due to their unique screening compared to their bulk counterparts. Additionally, accurate treatment of the dielectric response is crucial for developing and applying screened-exchange dielectric-dependent range-separated hybrid functionals (SE-DD-RSH) for vdW materials. In this work, we introduce a SE-DD-RSH functional to the 2D vdW materials like MoS2, WS2, hBN, black phosphorus (BP), and \b{eta}-InSe. By accounting for in-plane and out-of-plane dielectric responses, our method achieves accuracy comparable to advanced many-body techniques like G0 W0 and BSE@G0 W0 at a lower computational cost. We demonstrate improved band gap predictions and optical absorption spectra for both bulk and layered structures, including some heterostructures like MoS2/WS2 . This approach offers a practical and precise tool for exploring electronic and optical phenomena in 2D materials, paving the way for efficient computational studies of layered systems.