Theoretical modeling of spatial and temperature dependent exciton energy in coupled quantum wells

TL;DR

This paper presents a theoretical model explaining the nonmonotonic temperature dependence of exciton energy in coupled quantum wells, aligning well with recent experimental observations and highlighting the roles of two- and three-body interactions.

Contribution

It introduces a novel theoretical framework incorporating temperature-dependent interactions to explain exciton energy behavior in coupled quantum wells.

Findings

Attractive two-body and repulsive three-body interactions explain energy trends.

Exciton energy maxima occur at brightest regions, matching experiments.

The model accounts for nonmonotonic temperature dependence of exciton energy.

Abstract

Motivated by a recent experiment of spatial and temperature dependent average exciton energy distribution in coupled quantum wells [S. Yang \textit{et al.}, Phys. Rev. B \textbf{75}, 033311 (2007)], we investigate the nature of the interactions in indirect excitons. Based on the uncertainty principle, along with a temperature and energy dependent distribution which includes both population and recombination effects, we show that the interplay between an attractive two-body interaction and a repulsive three-body interaction can lead to a natural and good account for the nonmonotonic temperature dependence of the average exciton energy. Moreover, exciton energy maxima are shown to locate at the brightest regions, in agreement with the recent experiments. Our results provide an alternative way for understanding the underlying physics of the exciton dynamics in coupled quantum wells.