Electronic States and Spatial Charge Distribution of Single Mn Impurity in Diluted Magnetic Semiconductors

The electronic and magnetic properties as well as the spatial charge distribution of single Mn impurity in III--V diluted magnetic semiconductors are obtained when the degeneracy of the p orbits contributed from the four nearest-neighbouring As(N) atoms is taken into account. We show that in the ground state, the Mn spin is strongly antiferromagnetically coupled to the surrounding As(N) atoms when the p-d hybridization V_pd is large and both the hole level E_v and the impurity level E_d are close to the Fermi energy. The spatial charge distribution of the Mn acceptor in the (110) plane is non-spherically symmetric, in good agreement with the recent STM images.