Impurity-enhanced Aharonov-Bohm effect in neutral quantum-ring magnetoexcitons

TL;DR

This paper investigates how impurity scattering influences the photoluminescence of magnetoexcitons in quantum rings and quantum dots, revealing impurity effects that enhance emission and explain experimental observations.

Contribution

It demonstrates that impurities induce PL in dark states and cause spectral features absent in ideal systems, providing new insights into excitonic behavior under magnetic fields.

Findings

Impurities enhance PL intensity in dark magnetic field regions.

Impurity-induced anticrossings cause peaks and valleys in PL spectra.

Behavior explains recent experimental features in magnetoexcitons.

Abstract

We study the role of impurity scattering on the photoluminescence (PL) emission of polarized magnetoexcitons. We consider systems where both the electron and hole are confined on a ring structure (quantum rings) as well as on a type-II quantum dot. Despite their neutral character, excitons exhibit strong modulation of energy and oscillator strength in the presence of magnetic fields. Scattering impurities enhance the PL intensity on otherwise "dark" magnetic field windows and non-zero PL emission appears for a wide magnetic field range even at zero temperature. For higher temperatures, impurity-induced anticrossings on the excitonic spectrum lead to unexpected peaks and valleys on the PL intensity as function of magnetic field. Such behavior is absent on ideal systems and can account for prominent features in recent experimental results.