Quantum diffusion of dipole-oriented indirect excitons in coupled quantum wells

TL;DR

This paper develops a quantum diffusion model for dipole-oriented indirect excitons in coupled quantum wells, deriving a diffusion equation, estimating the diffusion coefficient, and showing how dipole interactions screen disorder, with numerical results for GaAs/AlGaAs wells.

Contribution

It introduces a microscopic quantum diffusion model for excitons in coupled quantum wells, including a modified Einstein relation and analysis of dipole interactions.

Findings

Derived a quantum diffusion equation for excitons.

Estimated the self-diffusion coefficient in quantum wells.

Showed dipole interactions screen disorder effects.

Abstract

A model for diffusion of statistically-degenerate excitons in (coupled) quantum wells is proposed and analysed. Within a microscopic approach, we derive a quantum diffusion equation, calculate and estimate the self-diffusion coefficient for excitons in quantum wells and derive a modified Einstein relation adapted to statistically-degenerated quasi-two-dimensional bosons. It is also shown that the dipole-dipole interaction of indirect excitons effectively screens long-range-correlated disorder in quantum wells. Numerical calculations are given for indirect excitons in GaAs/AlGaAs coupled quantum wells.