Interplay between periodicity and nonlinearity of indirect excitons in coupled quantum wells

TL;DR

This paper explores how the combination of periodic potentials and nonlinear interactions influences the localization-delocalization transition of indirect excitons in coupled quantum wells, providing a theoretical explanation aligned with recent experiments.

Contribution

It introduces a model incorporating both two-body attraction and three-body repulsion to explain exciton behavior in lattice potentials, advancing understanding of exciton dynamics.

Findings

Model explains localization-delocalization transition of excitons.

Photoluminescent energy increases with exciton density.

Interaction energy approaches lattice amplitude at transition.

Abstract

Inspired by a recent experiment of localization-delocalization transition (LDT) of indirect excitons in lateral electrostatic lattices [M. Remeika \textit{et al.}, Phys. Rev. Lett. \textbf{102}, 186803 (2009)], we investigate the interplay between periodic potential and nonlinear interactions of indirect excitons in coupled quantum wells. It is shown that the model involving both attractive two-body and repulsive three-body interactions can lead to a natural account for the LDT of excitons across the lattice when reducing lattice amplitude or increasing particle density. In addition, the observations that the smooth component of the photoluminescent energy increases with increasing exciton density and exciton interaction energy is close to the lattice amplitude at the transition are also qualitatively explained. Our model provides an alternative way for understanding the underlying physics of the exciton dynamics in lattice potential wells.