Charge and spin distributions in GaMnAs/GaAs Ferromagnetic Multilayers

TL;DR

This study models the charge and spin distributions in ferromagnetic GaMnAs/GaAs multilayers using a self-consistent electronic structure calculation, revealing strong spin polarization and layer-dependent charge localization.

Contribution

It introduces a self-consistent Luttinger-Kohn model approach to analyze charge and spin distributions in ferromagnetic multilayer structures with high Mn concentration.

Findings

Strong spin polarization observed in the multilayers.

Charge mainly localized in GaMnAs layers.

Distribution depends on layer widths and multilayer number.

Abstract

A self-consistent electronic structure calculation based on the Luttinger-Kohn model is performed on GaMnAs/GaAs multilayers. The Diluted Magnetic Semiconductor layers are assumed to be metallic and ferromagnetic. The high Mn concentration (considered as 5% in our calculation) makes it possible to assume the density of magnetic moments as a continuous distribution, when treating the magnetic interaction between holes and the localized moment on the Mn(++) sites. Our calculation shows the distribution of heavy holes and light holes in the structure. A strong spin-polarization is observed, and the charge is concentrated mostly on the GaMnAs layers, due to heavy and light holes with their total angular momentum aligned anti-parallel to the average magnetization. The charge and spin distributions are analyzed in terms of their dependence on the number of multilayers, the widths of the GaMnAs and GaAs layers, and the width of lateral GaAs layers at the borders of the structure.