Polaron-induced changes in moiré exciton propagation in twisted van der Waals heterostructures

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Main Authors: Knorr, Willy, Brem, Samuel, Meneghini, Giuseppe, Malic, Ermin
Format: Preprint
Published: 2024
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author Knorr, Willy
Brem, Samuel
Meneghini, Giuseppe
Malic, Ermin
author_facet Knorr, Willy
Brem, Samuel
Meneghini, Giuseppe
Malic, Ermin
contents Twisted transition metal dichalcogenides (TMDs) present an intriguing platform for exploring excitons and their transport properties. By introducing a twist angle, a moiré superlattice forms, providing a spatially dependent exciton energy landscape. Based on a microscopic many-particle theory, we investigate in this work polaron-induced changes in exciton transport properties in the MoSe$_2$/WSe$_2$ heterostructure. We demonstrate that polaron formation and the associated enhancement of moiré excitonic mass lead to a significant band flattening. As a result, the hopping rate and the propagation velocity undergo noticeable temperature and twist-angle dependent changes. We predict a reduction of the hopping strength ranging from 80% at a twist angle of 1$^\circ$ to 30% at 3$^\circ$ at room temperature. The provided microscopic insights into the spatio-temporal exciton dynamics in presence of a moiré potential further deepens our understanding of the intriguing moiré exciton physics.
format Preprint
id arxiv_https___arxiv_org_abs_2401_07703
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Polaron-induced changes in moiré exciton propagation in twisted van der Waals heterostructures
Knorr, Willy
Brem, Samuel
Meneghini, Giuseppe
Malic, Ermin
Mesoscale and Nanoscale Physics
Twisted transition metal dichalcogenides (TMDs) present an intriguing platform for exploring excitons and their transport properties. By introducing a twist angle, a moiré superlattice forms, providing a spatially dependent exciton energy landscape. Based on a microscopic many-particle theory, we investigate in this work polaron-induced changes in exciton transport properties in the MoSe$_2$/WSe$_2$ heterostructure. We demonstrate that polaron formation and the associated enhancement of moiré excitonic mass lead to a significant band flattening. As a result, the hopping rate and the propagation velocity undergo noticeable temperature and twist-angle dependent changes. We predict a reduction of the hopping strength ranging from 80% at a twist angle of 1$^\circ$ to 30% at 3$^\circ$ at room temperature. The provided microscopic insights into the spatio-temporal exciton dynamics in presence of a moiré potential further deepens our understanding of the intriguing moiré exciton physics.
title Polaron-induced changes in moiré exciton propagation in twisted van der Waals heterostructures
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2401.07703