The effect of As antisites in this dilute magnetic semiconductor was studied within density functional theory, using the local spin density approximation. It was found, in the case of an homogeneous distribution of Mn ions, that ferromagnetism was weakened by the presence of the antisites. This was attributed to compensation of the free holes which mediated the long-range ferromagnetic order. On the other hand, when two Mn ions were coupled through only one As ion, the ferromagnetic and antiferromagnetic states were comparable in energy. In this case, the magnetic ground state depended upon the position of the As antisites relative to Mn atoms, and upon the As antisite concentration.

Influence of the Local As Antisite Distribution on Ferromagnetism in (Ga,Mn)As. S.Sanvito, N.A.Hill: Applied Physics Letters, 2001, 78[22], 3493-5