Twistronics: Manipulating the Electronic Properties of Two-dimensional Layered Structures through their Twist Angle

TL;DR

This paper introduces a new computational method to analyze the electronic properties of twisted 2D layered materials, enabling the study of incommensurate structures and their density of states variations with twist angle.

Contribution

It presents a general, parameter-free approach for calculating the electronic density of states in aperiodic 2D layered materials derived from ab initio methods.

Findings

Method effectively models incommensurate 2D structures.

Density of states varies with twist angle and local configuration.

Application demonstrated on graphene and MoS2.

Abstract

The ability in experiments to control the relative twist angle between successive layers in two-dimensional (2D) materials offers a new approach to manipulating their electronic properties; we refer to this approach as "twistronics". A major challenge to theory is that, for arbitrary twist angles, the resulting structure involves incommensurate (aperiodic) 2D lattices. Here, we present a general method for the calculation of the electronic density of states of aperiodic 2D layered materials, using parameter-free hamiltonians derived from ab initio density-functional theory. We use graphene, a semimetal, and MoS$_2$, a representative of the transition metal dichalcogenide (TMDC) family of 2D semiconductors, to illustrate the application of our method, which enables fast and efficient simulation of multi-layered stacks in the presence of local disorder and external fields. We comment on the interesting features of their Density of States (DoS) as a function of twist-angle and local configuration and on how these features can be experimentally observed.