Twistronics of Janus transition metal dichalcogenide bilayers

TL;DR

This paper develops a comprehensive first-principle continuum theory for twisted Janus TMD bilayers, revealing how moiré patterns influence electronic properties and enable novel quantum phenomena.

Contribution

It introduces a high-throughput method to generate and analyze continuum models for various Janus TMD bilayers, incorporating effects like lattice relaxation and spin-orbit coupling.

Findings

Moiré physics depends on composition, stacking, and twist angle.

Emergent symmetries lead to different miniband network structures.

Rashba spin-orbit effects can dominate at small twist angles.

Abstract

Twisted multilayers of two-dimensional (2D) materials are an increasingly important platform for investigating quantum phases of matter, and in particular, strongly correlated electrons. The moir\'e pattern introduced by the relative twist between layers creates effective potentials of long-wavelength, leading to electron localization. However, in contrast to the abundance of 2D materials, few twisted heterostructures have been studied until now. Here we develop a first-principle continuum theory to study the electronic bands introduced by moire patterns of twisted Janus transition metal dichalcogenides (TMD) homo- and hetero-bilayers. The model includes lattice relaxation, stacking-dependent effective mass, and Rashba spin-orbit coupling. We then perform a high-throughput generation and characterization of DFT-extracted continuum models for more than a hundred possible combinations of materials and stackings. Our model predicts that the moir\'e physics and emergent symmetries depend on chemical composition, vertical layer orientation, and twist angle, so that the minibands wavefunctions can form triangular, honeycomb, and Kagome networks. Rashba spin-orbit effects, peculiar of these systems, can dominate the moir\'e bandwidth at small angles. Our work enables the detailed investigation of Janus twisted heterostructures, allowing the discovery and control of novel electronic phenomena.