Magneto-spatial dispersion of quantum wells

TL;DR

This paper investigates how magneto-spatial dispersion causes polarization conversion of light reflected from quantum wells, highlighting the role of structure asymmetry and excitonic resonance effects.

Contribution

It demonstrates that magneto-spatial dispersion in quantum wells arises from structure inversion asymmetry and excitonic effects, providing a microscopic understanding of polarization conversion.

Findings

Polarization conversion is influenced by magnetic field and light propagation direction.

Magneto-spatial dispersion is enhanced near heavy-hole exciton resonance.

The degree of asymmetry is quantified for GaAs/AlGaAs and CdTe quantum wells.

Abstract

Polarization conversion of light reflected from quantum wells governed by both magnetic field and light propagation direction is observed. We demonstrate that the polarization conversion is caused by the magneto-spatial dispersion in quantum wells which manifests itself in the reflection coefficient contribution bilinear in the in-plane components of the magnetic field and the light wavevector. The magneto-spatial dispersion is shown to arise due to structure inversion asymmetry of the quantum wells. The effect is resonantly enhanced in the vicinity of the heavy-hole exciton. We show that microscopically the magneto-spatial dispersion is caused by the mixing of heavy- and light-hole states in the quantum well due to both orbital effect of the magnetic field and the in-plane hole motion. The degree of the structure inversion asymmetry is determined for GaAs/AlGaAs and CdTe quantum wells.