Energetics, electronic structure and local magnetism of single 3d impurity in GaAs

A real-space first-principles method based on density functional theory has been used to study the energetics, the electronic structure and the magnetic property of single 3d impurity in a GaAs host (with Ga substituted by Cr, Mn, Fe, Co, and Ni, respectively). It is found that Mn exhibits the largest exchange splitting in 3d orbitals, while Fe, Co, and Ni are almost nonmagnetic. The calculated substitutional formation energies are 3.87, 3.21, 1.36, 1.41, 0.37 eV, and the calculated local magnetic moments are 3.25, 4.26, -0.01, -0.03 and -0.01 μB, for Cr, Mn, Fe, Co and Ni, respectively. For a good understanding on the local magnetism of the 3d impurity, we analyzed the bonding characteristics and the charge transfer property in detail, and found that the hybridizations between 3d impurity and its neighboring As atoms play an important role