Anisotropy of heavy hole spin splitting and interference effects of optical polarization in semiconductor quantum wells subjected to an in-plane magnetic field

TL;DR

This paper develops a microscopic theory explaining optical polarization anisotropy in semiconductor quantum wells under in-plane magnetic fields, highlighting two mechanisms involving electron-hole interactions and light-hole admixture, with implications for experimental observations.

Contribution

The paper introduces a comprehensive microscopic model accounting for two distinct sources of optical polarization anisotropy in quantum wells subjected to in-plane magnetic fields, advancing understanding of polarization effects.

Findings

Polarization effects can reach maximum at low temperatures with a single transition.

Admixture of light-hole states contributes to polarization independently of temperature and magnetic field.

Different mechanisms of heavy hole splitting exhibit strong polarization anisotropy.

Abstract

Strong effects of optical polarization anisotropy observed previously in the quantum wells subjected to the in-plane magnetic field arrive at complete description within microscopic approach. Theory we develop involves two sources of optical polarization. First source is due to correlations between electron and heavy hole (HH) phases of $\psi $-functions arising due to electron Zeeman spin splitting and joint manifestation of low-symmetry and Zeeman interactions of HH in an in-plane magnetic field. In this case, four possible phase-controlled electron-HH transitions constitute the polarization effect, which can reach its maximal amount ($\pm $1) at low temperatures when only one transition survives. Other polarization source stems from the admixture of excited light-holes (LH) states to HH by low-symmetry interactions. The contribution of this mechanism to total polarization is relatively small but it can be independent of temperature and magnetic field. Analysis of different mechanisms of HH splitting exhibits their strong polarization anisotropy. Joint action of these mechanisms can result in new peculiarities, which should be taken into account for explanation of different experimental situations.