Moir\'e and beyond in transition metal dichalcogenide twisted bilayers

TL;DR

This review discusses the opto-electronic properties of moiré excitons in twisted bilayer transition metal dichalcogenides, highlighting recent evidence, nanoscale mapping, and potential for creating novel physical states.

Contribution

It provides a comprehensive overview of moiré excitons in TMD twisted bilayers, emphasizing recent experimental findings and future research directions.

Findings

Evidence of moiré excitons in localized states

Nanoscale mapping of moiré superlattice

Potential for controlling novel physical states

Abstract

Fabricating van der Waals (vdW) bilayer heterostructures (BL-HS) by stacking the same or different two-dimensional (2D) layers, offers a unique physical system with rich electronic and optical properties. Twist-angle between component layers has emerged as a remarkable parameter that can control the period of lateral confinement, and nature of the exciton (Coulomb bound electron-hole pair) in reciprocal space thus creating exotic physical states including moir\'e excitons. In this review article, we focus on opto-electronic properties of excitons in transition metal dichalcogenide (TMD) semiconductor twisted BL-HS. We look at existing evidence of moir\'e excitons in localized and strongly correlated states, and at nanoscale mapping of moir\'e superlattice and lattice-reconstruction. This review will be helpful in guiding the community as well as motivating work in areas such as near-field optical measurements and controlling the creation of novel physical states.