Density Enhanced Diffusion of Dipolar Excitons within a One-Dimensional Channel

TL;DR

This study explores how dipolar excitons diffuse differently in 1D and 2D quantum well channels, revealing linear behavior in 1D and non-linear in 2D, with diffusion in 1D enhanced by exciton density.

Contribution

It demonstrates that dipolar exciton diffusion in 1D channels is linearly dependent on density and exceeds 2D diffusion, highlighting the role of disorder screening.

Findings

1D diffusion is linear in time even at high densities.

1D diffusion coefficient is much higher than in 2D and depends linearly on density.

Screening of disorder by dipolar excitons influences diffusion behavior.

Abstract

We experimentally investigate the lateral diffusion of dipolar excitons in coupled quantum wells in two (2D) and one (1D) dimensions. In 2D, the exciton expansion obeys non-linear temporal dynamics due to the repulsive dipole pressure at a high exciton density, in accordance with recent reports. In contrast, the observed 1D expansion behaves linearly in time even at high exciton densities. The corresponding 1D diffusion coefficient exceeds the one in 2D by far and depends linearly on the exciton density. We attribute the findings to screening of quantum well disorder by the dipolar excitons.