Imaging dynamic exciton interactions and coupling in transition metal dichalcogenides

TL;DR

This study uses multi-dimensional coherent imaging spectroscopy to analyze exciton interactions in TMD monolayers and heterostructures, revealing uniform coupling properties despite inhomogeneity, supporting their potential in quantum technologies.

Contribution

It demonstrates the application of MDCIS to map exciton interactions and coupling in TMDs, highlighting their robustness and suitability for scalable quantum devices.

Findings

Coupling strength and exciton lifetimes are uniform across samples.

Inhomogeneity does not significantly affect exciton coupling.

Sample inhomogeneity may hinder device scalability.

Abstract

Transition metal dichalcogenides (TMDs) are regarded as a possible materials platform for quantum information science and related device applications. In TMD monolayers, the dephasing time and inhomogeneity are crucial parameters for any quantum information application. In TMD heterostructures, coupling strength and interlayer exciton lifetimes are also parameters of interest. However, many demonstrations in TMDs can only be realized at specific spots on the sample, presenting a challenge to the scalability of these applications. Here, using multi-dimensional coherent imaging spectroscopy (MDCIS), we shed light on the underlying physics - including dephasing, inhomogeneity, and strain - for a MoSe$_2$ monolayer and identify both promising and unfavorable areas for quantum information applications. We furthermore apply the same technique to a MoSe$_2$/WSe$_2$ heterostructure. Despite the notable presence of strain and dielectric environment changes, coherent and incoherent coupling, as well as interlayer exciton lifetimes are mostly robust across the sample. This uniformity is despite a significantly inhomogeneous interlayer exciton photoluminescence distribution that suggests a bad sample for device applications. This robustness strengthens the case for TMDs as a next-generation materials platform in quantum information science and beyond.