Self-compensating incorporation of Mn in Ga(1-x)Mn(x)As

摘要

We consider hypothetical Ga7MnAs8, Ga16MnAs16, and Ga14Mn3As16 crystals withMn in a substitutional, interstitial, and both positions. Spin-polarized FPLAPWcalculations were used to obtain their electronic structure. We show that theinterstitial Mn acts as a double donor and compensates the holes created by twoMn atoms in substitutional positions. This explains why the number of holes inGa(1-x)Mn(x)As is much smaller than x. The presence of interstitial atoms mayalso be the reason for the lattice expansion with increasing content of Mn. Thedifferences in electronic behavior of substitutional and interstitial Mn arediscussed.