Efficient $G_0W_0$ and BSE calculations of heterostructures within an all-electron framework

TL;DR

This paper presents an efficient all-electron method for calculating electronic and optical properties of 2D heterostructures using $G_0W_0$ and BSE within the (L)APW framework, enabling high-precision results at reduced computational cost.

Contribution

The authors extend an existing polarizability calculation approach to the (L)APW method and implement it for $G_0W_0$ and BSE, improving efficiency for large heterostructures.

Findings

Accurate optical spectra for bilayer WSe$_2$ and pyridine@MoS$_2$.

Comparable results to exact reference calculations.

Reduced computational cost for all-electron heterostructure simulations.

Abstract

The combination of two-dimensional materials into heterostructures offers new opportunities for the design of optoelectronic devices with tunable properties. However, computing electronic and optical properties of such systems using state-of-the-art methodology is challenging due to their large unit cells. This is in particular so for highly-precise all-electron calculations within the framework of many-body perturbation theory, which come with high computational costs. Here, we extend an approach that allows for the efficient calculation of the non-interacting polarizability, previously developed for planewave basis sets, to the (linearized) augmented planewave (L)APW method. This approach is based on an additive ansatz, which computes and superposes the polarizabilities of the individual components in their respective unit cells. We implement this formalism in the $G_0W_0$ module of the exciting code and implement an analogous approach for BSE calculations. This allows the calculation of highly-precise optical spectra at low cost. So-obtained results of the quasi-particle band structure and optical spectra are demonstrated for bilayer WSe$_2$ and pyridine@MoS$_2$ in comparison with exact reference calculations.