Curie temperatures of the concentrated and diluted Kondo-lattice model as a possible candidate to describe magnetic semiconductors and metals

TL;DR

This paper develops a theoretical model for carrier-mediated ferromagnetism in local moment systems, enabling calculation of Curie temperatures and their dependence on parameters, with qualitative agreement to experimental data on GaMnAs.

Contribution

It introduces a combined equation of motion and coherent potential approximation method to model the electronic subsystem of the Kondo lattice, allowing for the calculation of Curie temperatures in magnetic semiconductors and metals.

Findings

Qualitative agreement with experimental Curie temperatures of GaMnAs.

The model predicts Curie temperature dependence on hole density.

Provides a framework for understanding magnetic ordering in Kondo-lattice systems.

Abstract

We present a theory to model carrier mediated ferromagnetism in concentrated or diluted local moment systems. The electronic subsystem of the Kondo lattice model is described by a combined equation of motion / coherent potential approximation method. Doing this we can calculate the free energy of the system and its minimum according to the magnetization of the local moments. Thus also the Curie temperature can be determined and its dependence on important model parameters. We get qualitative agreement with the Curie temperatures' experimental values of Ga$_{1-x}$Mn$_x$As for a proper hole density.