摘要

The electronic structures and tetragonal distortion for the full Heusler compound Ti2NiGa have been studied by first principles calculations. The results predict that Ti2NiGa presents half-metallicity within the lattice constants range of 5.70 to 6.50 together with the integral magnetic moment 3.00 mu (B) . The total magnetic moment (M (t) ) and the number of valence electrons (Z (t) ) of Ti2NiGa obey the Slater-Pauling (SP) rule of M (t) =Z (t) -18 very well. The results of tetragonal distortion indicate that the half-metallicity of Ti2NiGa alloy can be retained in the range of the c/a ratio from 0.85 to 1.20. Ti(A) atom has dominating contribution to the magnetism of Ti2NiGa even when the lattice constant and the structure experience large change. In the presence of vacancy defects, Ti2NiGa can still maintain half-metallicity.