Indirect exchange in GaMnAs bilayers via spin-polarized inhomogeneous hole gas: Monte Carlo simulation

TL;DR

This paper investigates how spin-polarized hole gases mediate indirect exchange interactions in GaMnAs bilayers, revealing ferromagnetic order and interlayer coupling through Monte Carlo simulations and perturbative calculations.

Contribution

It introduces a self-consistent Monte Carlo simulation approach to study indirect exchange mediated by spin-polarized holes in GaMnAs bilayers, accounting for electronic and magnetic interactions.

Findings

Internal ferromagnetic order within layers

Parallel magnetization alignment between layers

Ferromagnetic coupling persists in thin layers

Abstract

The magnetic order resulting from an indirect exchange between magnetic moments provided by spin-polarized hole gas in the metallic phase of a GaMnAs double layer structure is studied via Monte Carlo simulation. The coupling mechanism involves a perturbative calculation in second order of the interaction between the magnetic moments and carriers (holes). We take into account a possible polarization of the hole gas due to the existence of an average magnetization in the magnetic layers, establishing, in this way, a self-consistency between the magnetic order and the electronic structure. That interaction leads to an internal ferromagnetic order inside each layer, and a parallel arrangement between their magnetizations, even in the case of thin layers. This fact is analyzed in terms of the inter- and intra-layer interactions.