One-Dimensional Moir\'e Excitons in Transition-Metal Dichalcogenide Heterobilayers

TL;DR

This paper demonstrates the existence of one-dimensional moiré excitons in transition-metal dichalcogenide heterobilayers, showing how strain can be used to engineer and control their optical properties for quantum applications.

Contribution

It provides direct real-space imaging evidence of 1D moiré potentials and excitons, revealing strain-tunable moiré landscapes in TMDC heterobilayers.

Findings

1D moiré excitons exhibit linear polarization and higher PL intensity.

Strain can transform 0D quantum traps into 1D quantum wires.

Moiré potentials are highly responsive to small uniaxial strains.

Abstract

The formation of interfacial moir\'e patterns from angular and/or lattice mismatch has become a powerful approach to engineer a range of quantum phenomena in van der Waals heterostructures. For long-lived and valley-polarized interlayer excitons in transition-metal dichalcogenide (TMDC) heterobilayers, signatures of quantum confinement by the moir\'e landscape have been reported in recent experimental studies. Such moir\'e confinement has offered the exciting possibility to tailor new excitonic systems, such as ordered arrays of zero-dimensional (0D) quantum emitters and their coupling into topological superlattices. A remarkable nature of the moir\'e potential is its dramatic response to strain, where a small uniaxial strain can tune the array of quantum-dot-like 0D traps into parallel stripes of one-dimensional (1D) quantum wires. Here, we present direct evidence for the 1D moir\'e potentials from real space imaging and the corresponding 1D moir\'e excitons from photoluminescence (PL) emission in MoSe2/WSe2 heterobilayers. Whereas the 0D moir\'e excitons display quantum emitter-like sharp PL peaks with circular polarization, the PL emission from 1D moir\'e excitons has linear polarization and two orders of magnitude higher intensity. The results presented here establish strain engineering as a powerful new method to tailor moir\'e potentials as well as their optical and electronic responses on demand.