Enhanced robustness of half-metallicity in VBr3 nanowires by strains and transition metal doping

Abstract

The study of half-metallic behavior for transition metal tribromide nanowires is of great significance to the basic research and application in spintronics. We have theoretically investigated the spin transport properties of half-metallic VBr₃ nanowires sandwiched between Au(100) electrodes. For the VBr₃ nanowire with a length of 24.75 Å, the spin-filter efficiency (SFE) achieves 100% when the applied bias is less than 0.4 V. The robustness of half-metallic behavior in VBr₃ nanowires is investigated by strains and transition metal doping. The bias range of VBr₃ nanowires exhibiting perfect SFE is extended by tensile strains, while it becomes narrower under compressive strains. For VBr₃ nanowires doped with Co and Cr, the bias range with ideal SFE is significantly broadened at a low doping concentration. In particular, the VBr₃ nanowire doped with 1 Cr atom exhibits perfect SFE in an extremely wide bias range of 0–1.0 V. Our results show that the robustness of half-metallicity of VBr₃ nanowires can be improved by tensile strains or certain doping, which provides promising ways for further design of high-performance spintronic devices.