Drift mobility of long-living excitons in coupled GaAs quantum wells

TL;DR

This study demonstrates high-mobility transport of indirect excitons in coupled GaAs quantum wells, revealing temperature-dependent mobility behavior and the ability to control exciton flow with voltage-induced potential gradients.

Contribution

It introduces a method to define tunable in-plane potential gradients for excitons using a resistive top gate and explores exciton drift dynamics with high spatial and temporal resolution.

Findings

Excitonic mobility exceeds 10^5 cm^2/Vs at temperatures below 10 K

Mobility decreases with increasing temperature due to exciton-phonon scattering

Voltage-tunable potential gradients effectively control exciton transport

Abstract

We observe high-mobility transport of indirect excitons in coupled GaAs quantum wells. A voltage-tunable in-plane potential gradient is defined for excitons by exploiting the quantum confined Stark effect in combination with a lithographically designed resistive top gate. Excitonic photoluminescence resolved in space, energy, and time provides insight into the in-plane drift dynamics. Across several hundreds of microns an excitonic mobility of >10^5 cm2/eVs is observed for temperatures below 10 K. With increasing temperature the excitonic mobility decreases due to exciton-phonon scattering.