Quantum interference effect on exciton transport in monolayer semiconductors

TL;DR

This paper theoretically investigates how quantum interference, specifically weak localization, affects exciton transport in monolayer transition metal dichalcogenides, revealing significant effects at higher temperatures.

Contribution

It provides a theoretical calculation of quantum interference effects on exciton diffusion, considering realistic scattering mechanisms in atomically-thin semiconductors.

Findings

Quantum interference decreases exciton diffusion coefficient.

Effect becomes more significant with increasing temperature.

Quantum contribution is substantial in current monolayer and bilayer materials.

Abstract

We study theoretically weak localization of excitons in atomically-thin transition metal dichalcogenides. The constructive interference of excitonic de Broglie waves on the trajectories forming closed loops results in a decrease of the exciton diffusion coefficient. We calculate the interference contribution to the diffusion coefficient for the experimentally relevant situation of exciton scattering by acoustic phonons and static disorder. For the acoustic phonon scattering, the quantum interference becomes more and more important with increasing the temperature. Our estimates show that the quantum contribution to the diffusion coefficient is considerable for the state-of-the-art monolayer and bilayer transition metal dichalcogenides.