Density-functional theory study of long-range ferromagnetic properties in Mg-doped SiC

Using the full-potential linearized augmented plane wave method, we study the magnetism and electronic structures of Mg-doped 3C-SiC. The results show that the SiC doped with an isolated Mg atom produces a total magnetic moment of 2.0 μB and introduces spin-polarized 2p states in the system. The origin of the magnetic moments is the holes in the MgC4 tetrahedron induced by Mg doping. The long-range ferromagnetic interaction between Mg atoms can be attributed to the hole-mediated double exchange through the strong p-p interaction between Mg and neighboring carbons.