Giant Zeeman splitting of light holes in GaAs/AlGaAs quantum wells

TL;DR

This paper presents a theory showing that the Zeeman splitting of light holes in GaAs/AlGaAs quantum wells can be significantly larger and non-linear at low magnetic fields due to subband interactions.

Contribution

The paper introduces a new theoretical model for light-hole g-factors in quantum wells, accounting for subband mixing and interface effects, revealing enhanced and non-linear Zeeman splitting.

Findings

Light-hole g-factor can greatly exceed bulk values.

Zeeman splitting becomes non-linear at low magnetic fields.

Proximity of light-hole and heavy-hole subbands influences splitting.

Abstract

We have developed a theory of the longitudinal $g$ factor of light holes in semiconductor quantum wells. It is shown that the absolute value of the light-hole $g$-factor can strongly exceed its value in the bulk and, moreover, the dependence of the Zeeman splitting on magnetic field becomes non-linear in relatively low fields. These effects are determined by the proximity of the ground light-hole subband, $lh1$, to the first excited heavy-hole subband, $hh2$, in GaAs/AlGaAs-type structures. The particular calculations are performed in the framework of Luttinger Hamiltonian taking into account both the magnetic field-induced mixing of $lh1$ and $hh2$ states and the mixing of these states at heterointerfaces, the latter caused by chemical bonds anisotropy. A theory of magneto-induced reflection and transmission of light through the quantum wells for the light-hole-to-electron absorption edge is also presented.