The dielectric genome of van der Waals heterostructures

TL;DR

This paper introduces a multi-scale ab-initio method to accurately compute dielectric properties of large, incommensurable van der Waals heterostructures, enabling insights into their electronic behavior and interactions.

Contribution

It presents a novel multi-scale approach for calculating dielectric functions of complex, large-scale vdWHs with ab-initio accuracy, overcoming previous computational limitations.

Findings

Demonstrates 2D-3D dielectric transition in MoS2

Shows hybridization of quantum plasmons in graphene/hBN

Reveals substrate screening effects on WS2 excitons

Abstract

Vertical stacking of two-dimensional (2D) crystals, such as graphene and hexagonal boron nitride, has recently lead to a new class of materials known as van der Waals heterostructures (vdWHs) with unique and highly tunable electronic properties. Abinitio calculations should in principle provide a powerful tool for modeling and guiding the design of vdWHs, but in their traditional, form such calculations are only feasible for commensurable structures with a few layers. Here we show that the dielectric properties of realistic, incommensurable vdWHs comprising hundreds of layers can be calculated with ab-initio accuracy using a multi-scale approach where the dielectric functions of the individual layers (the dielectric building blocks) are coupled simply via their long-range Coulomb interaction. We use the method to illustrate the 2D- 3D dielectric transition in multi-layer MoS2 crystals, the hybridization of quantum plasmons in large graphene/hBN heterostructures, and to demonstrate the intricate effect of substrate screening on the non-Rydberg exciton series in supported WS2.