Tunable Magnetism and Half-Metallic Stability in Si-Doped Hg<sub>2</sub>CuTi-Type Ti<sub>2</sub>CoGa Alloy

Abstract

Using the ab-initio calculations within the density functional theory (DFT), we have investigated the electronic structure, magnetism and half-metallic stability of Si-doped Heusler compound Ti2CoGa with Hg2CuTi-type structure. The results revel that the lattice constants and total magnetic moments in per unit obey the Vegard’s rule and the Slater-Pauling rule well, respectively. The most stable half-metallicity occurs at doping concentration x=0.75 because the Fermi level is located at the middle of the spin-minority gap. Our studies also indicate that the competition between RKKY-type indirect exchange and direct hybridization of d-electronic atoms plays a dominating role in determining the magnetism.