Electronic structure and half-metallic property of Mn-doped (beta)-SiC diluted magnetic semiconductor

Using ab initio ultrasoft pseudopotential plane wave method, the effect of doping concentration of Mn on the magnetic properties of (beta)-SiC (SiC:Mn) was quantitatively investigated. It is found that the SiC:Mn shows stable ferromagnetism, and the total magnetic moment of SiC:Mn depends on the substitution site of Mn in the SiC lattice. Using the density of states calculation, it is shown that SiC:Mn has half-metallic properties for selected doping concentrations of 1.56, 3.13 and 6.25%, irrespective of substitution site. The conduction electron mobility of SiC:MnC was expected to be higher than that of SiC:MnSi. On the contrary, SiC:MnSi has a wider spin band gap compared to SiC:MnC. It is predicted that SiC with 12.5% Mn doping represents desirable characteristics for realizing spintronic devices, which include stable ferromagnetism, half-metallic properties, fast electron mobility and a wide spin band gap.