Tight-binding study of the magnetic properties of Mn-doped Ge

Abstract

A generalized tight-binding bond Stoner model satisfying charge self-consistence is used to study Mn-doped Ge. We fit the tight-binding parameters to first-principles nonmagnetic band structures of zinc blende MnGe, and then calculate the ferromagnetic and antiferromagnetic band structures with the local stoner model. The predicted band structures match the first-principles ferromagnetic and antiferromagnetic calculations of the MnGe well and reveal that the MnGe is a half-metallic ferromagnet with integer magnetic moment in Bohr magneton. Applied to low concentrations of Mn doping, this model produces good magnetic moments, spin-dependent density of states, and energetics for Mn doping concentrations down to 0.03125. These results are in agreement with corresponding first-principles calculations. This method can be applied to other transition-metal doped semiconductors.