Coexistence of half-metallicity and martensitic transition in Co2VGa1Sb (x = 0, 0.25 and 0.5) Heusler alloys: First-principles calculations combined with structural experiments

Abstract Herein, we have investigated, theoretically and experimentally, the influence of Sb-doping, at Ga-site, on crystal structure, martensitic transition (MT) and half-metallicity of Co 2 VGa 1− x Sb x ( x  = 0, 0.25 and 0.5) Heusler alloys. The results reveal that the Co-V-Ga-Sb alloys with x  = 0 and 0.25 exhibit typical half-metallicity, and at x  = 0.25 the density of states (DOS) show a wider band gap near the Fermi level in minority states, which implies that Co 2 VGa 0.75 Sb 0.25 is an efficient material with 100% spin polarization. Moreover, Co 2 VGa 0.5 Sb 0.5 exhibits a martensitic transformation from parent phase with L2 1 -type cubic structure to the D0 22 -type tetragonal structure at ∼347 K. In addition, the DOS of Co 2 VGa 0.5 Sb 0.5 also exhibit half-metallicity after expanding the lattice parameter by 2%. The unique features of Co 2 VGa 1− x Sb x Heusler alloys imply that these alloys are promising for high-efficiency spintronics and shape memory devices.