Curie temperatures of III-V diluted magnetic semiconductors calculated from first principles

Curie temperatures of the diluted magnetic semiconductors (Ga, Mn) As, (Ga, Mn) N, (Ga, Cr) As and (Ga, Cr) N are evaluated from first principles. The electronic structure is calculated in the local spin density approximation by using the Korringa-Kohn-Rostoker method combined with the coherent potential approximation to describe the substitutional and spin disorder. From the total energy differences between the ferromagnetic state and the spin-glass state, realistic estimations of Curie temperatures are achieved by using a mapping on the Heisenberg model in the mean-field approximation. Effects of additional carrier doping treatments are also investigated. Very large Curie temperatures are obtained, lying above room temperature for ( Ga, Mn) N, ( Ga, Cr) As and ( Ga, Cr) N. Upon hole doping the Curie temperature of (Ga, Mn) N further increases, while (Ga, Mn) As shows a plateau behavior.