Current-induced Magnetoexcitons in Mesoscopic Electron-hole Plasma

TL;DR

This paper reports a significant change in the optical response of a mesoscopic electron-hole plasma in GaAs/AlGaAs under magnetic field and electric current, revealing current-induced formation of excitons and trions due to Coulomb drag.

Contribution

It demonstrates how electric current induces local light hole accumulation and strong electron-hole coupling, leading to exciton and trion formation in a mesoscopic system.

Findings

Current causes a drastic change in emission spectra.

Light holes dominate emission under current.

Formation of excitons and trions due to Coulomb drag.

Abstract

A radical restructuring of the optical response of highly excited electron-hole plasma formed in a mesoscopic GaAs/AlGaAs channel in a quantizing magnetic field when an electric current flows in the channel has been discovered. In the absence of current, the emission spectra are caused by transitions between Landau levels formed in the conduction band and in the valence band of heavy holes. A critical electric current leads to a drastic change in the emission spectra with a predominant contribution from light holes. It is shown that the current causes local accumulation of light holes due to Coulomb drag, which leads to strong electron-hole coupling and, as a consequence, the formation of excitons and trions.