Confinement engineering of s-d exchange interactions in GaMnAs quantum wells

TL;DR

This paper investigates how quantum confinement in GaMnAs/AlGaAs quantum wells influences the s-d exchange interaction, revealing a dependence on confinement energy through experimental measurements and a band-mixing theoretical model.

Contribution

It provides systematic experimental data and a theoretical model showing the dependence of s-d exchange interactions on confinement energy in quantum wells.

Findings

s-d exchange interaction depends on well width and depth

The magnitude of N0alpha varies with confinement energy

Band-mixing model explains the confinement-induced kinetic exchange

Abstract

Recent measurements of coherent electron spin dynamics reveal an antiferromagnetic s-d exchange coupling between conduction band electrons and electrons localized on Mn{2+} impurities in GaMnAs quantum wells. Here we discuss systematic measurements of the s-d exchange interaction in GaMnAs/AlGaAs quantum wells with different confinement potentials using time-resolved Kerr rotation. Extending previous investigations of the dependence of the s-d exchange, N{0}alpha, on well width, we find that its magnitude also depends on well depth. Both phenomena reduce to a general dependence on confinement energy, described by a band-mixing model of confinement-induced kinetic exchange in the conduction band.