J. Magn. Magn. Mater.   238, 252 (2002)
 

Prediction of enhanced ferromagnetism in (Ga,Mn)As by

intrinsic defect manipulation

S. Sanvito, and Nicola A. Hill

In the diluted magnetic semiconductor (Ga,Mn)As the excess of As incorporated as As antisites (AsGa ) is responsible for the hole compensation. The AsGa defect can be transformed into a As interstitial Ga vacancy pair (As-V Ga) upon illumination. In this paper we study the effects of such a transition on the ferromagnetism of (Ga,Mn)As using density functional theory within the local spin density approximation. We find that the ferromagnetic order in (Ga,Mn)As is strongly enhanced if AsGa are transformed into As-VGa pairs, since the hole compensation is reduced. This suggests a valuable way to tune the carrier concentration and hence the Tc in (Ga,Mn)As, without changing the Mn concentration nor the microscopic configuration of the Mn ions.