Influence of Mn concentration on the electronic and magnetic properties of Mn doped beta -Ge(3)N(4): A first-principles study

The influence of Mn concentration on the electronic and magnetic properties of Mn doped beta -Ge(3)N(4) was investigated by using first-principles calculations based on density functional theory. Our results show that Mn atoms prefer occupying Ge sites and have a tendency to cluster. The electronic and magnetic properties of the system with Mn doping are closely related to Mn concentration. As Mn concentration increases from 5.56% to 11.11%, the conductivity of the system transforms from semiconductivity to half-metallicity, and the spin states of Mn 3d electrons also transit from low-spin to high-spin states. Our detailed analyses of electronic structure reveal that the ferromagnetic coupling between the Mn atoms induces the high spin-states of Mn 3d electrons and the half-metallicity of the system.