A Green’s function model for ferromagnetism and spin excitations of (Ga, Mn)As diluted magnetic semiconductors

We study (Ga,Mn)As diluted magnetic semiconductors in terms of the Ruderman–Kittel–Kasuya–Yosida quantum spin model in Green’s function approach.Random distributions of the magnetic atoms are treated by using an analytical average of magnetic configurations.Average magnetic moments and spin excitation spectra as functions of temperature can be obtained by solving self-consistent equations,and the Curie temperature TC is given explicitly.TC is proportional to magnetic atomic concentration,and there exists a maximum for TC as a function of carrier concentration.Applied to (Ga,Mn)As,the theoretical results are consistent with experiment and the experimental TC can be obtained with reasonable parameters.This modelling can also be applied to other diluted magnetic semiconductors.