Ferromagnetism in Dilute Magnetic Semiconductors

TL;DR

This paper investigates the ferromagnetic properties of Ga1-xMnxAs using a model Hamiltonian that considers impurity bands and exchange interactions, providing insights into transition temperatures and magnetization behavior.

Contribution

It introduces a mean field model incorporating impurity distribution effects to analyze ferromagnetism in dilute magnetic semiconductors.

Findings

Calculated transition temperatures as a function of Mn concentration.

Predicted magnetization behavior consistent with experimental data.

Highlighted the role of impurity distribution in ferromagnetic properties.

Abstract

We study the ferromagnetism of Ga1-xMnxAs by using a model Hamiltonian, based on an impurity band and the anti-ferromagnetic exchange interaction between the spins of Mn atoms and the charge carriers in the impurity band. Based on the mean field approach we calculate the spontaneous magnetization as a function of temperature and the ferromagnetic transition temperature as a function of the Mn concentration. The random distribution of Mn impurities is taken into account by Matsubara and Toyozawa theory of impurities in semiconductors. We compare our results with experiments and other theoretical findings.