Laterally Extended States of Interlayer Excitons in Reconstructed MoSe$_2$/WSe$_2$ Heterostructures

TL;DR

This study reveals that interlayer excitons in reconstructed MoSe₂/WSe₂ heterostructures can extend laterally beyond the moiré pattern, challenging the assumption of localized excitonic states due to atomic reconstruction.

Contribution

It demonstrates, through combined theoretical and experimental approaches, that excitonic states in reconstructed heterostructures are delocalized beyond the moiré periodicity, providing new insights into exciton behavior.

Findings

Excitonic states extend beyond the moiré pattern in reconstructed heterostructures.

Real-space calculations match cryogenic photoluminescence results.

Interlayer excitons show relaxation characteristics supported by experiments.

Abstract

Heterostructures made from 2D transition-metal dichalcogenides are known as ideal platforms to explore excitonic phenomena ranging from correlated moir\'e excitons to degenerate interlayer exciton ensembles. So far, it is assumed that the atomic reconstruction appearing in some of the heterostructures gives rise to a dominating localization of the exciton states. We demonstrate that excitonic states in reconstructed MoSe$_2$/WSe$_2$ heterostructures can extend well beyond the moir\'e periodicity of the investigated heterostructures. The results are based on real-space calculations yielding a lateral potential map for interlayer excitons within the strain-relaxed heterostructures and corresponding real-space excitonic wavefunctions. We combine the theoretical results with cryogenic photoluminescence experiments, which support the computed level structure and relaxation characteristics of the interlayer excitons.