Transient magnetoconductivity of photoexcited electrons

TL;DR

This paper theoretically investigates the transient magnetoconductivity of photoexcited two-dimensional electrons in quantum wells, predicting large-amplitude Hall oscillations caused by negative conductivity effects.

Contribution

It introduces a detailed theoretical model for transient magnetotransport considering electron relaxation and predicts novel Hall oscillations in photoexcited quantum wells.

Findings

Prediction of large-amplitude transient Hall oscillations.

Identification of frequencies in the magnetoplasmon range.

Analysis of effects of electron-phonon interactions on conductivity.

Abstract

Transient magnetotransport of two-dimensional electrons with partially-inverted distribution excited by an ultrashort optical pulse is studied theoretically. The time-dependent photoconductivity is calculated for GaAs-based quantum wells by taking into account the relaxation of electron distribution caused by non-elastic electron-phonon interaction and the retardation of the response due to momentum relaxation and due to a finite capacitance of the sample. We predict large-amplitude transient oscillations of the current density and Hall field (Hall oscillations) with frequencies corresponding to magnetoplasmon range, which are initiated by the instability owing to the absolute negative conductivity effect.