First principles study of intrinsic defects in (Ga,Mn)As

We present density functional calculations of the structural, electronic and magnetic properties of various intrinsic defects in (Ga,Mn)As. Our main finding is that As excess generally weakens the ferromagnetic coupling between Mn ions. Moreover, we find that the interaction is strongly dependent on the microscopic configuration of the Mn ions and the defects, suggesting that a mean field description is not always appropriate.