Electronic Structure and Half-Metallic Properties of Cubic Perovskite BaRu_1-XTi_xO₃ System

The electronic structures of the titanium-doped cubic perovskite ruthenates BaRu1-xTixO3 with x=0.125, 0.25, 0.375, 0.5, 0.625, 0.75, and 0.875 are investigated using the spin-polarized density functional theory within the pseudopotential plane wave method. It is found that a half-metallic phase appears in the 0.75- and 0.875-doped systems, and the origin of half-metallic property is the decrease of t2g bandwidth of Ru 4d states with the increase in x. In addition, the energy gap of BaRu0.25Ti0.75O3 is as large as 1.7 eV at the Fermi level in the up-spin density of states, which suggests a stable half-metallic phase can be obtained in the present systems.