Weyl semimetal phases and intrinsic spin-Hall conductivity in SbAs ordered alloys*

Weyl semimetal (WSM) phase in antimony arsenide ordered alloys Sb_1-xAs_x (x=0, 1/6, 1/3, 1/2, 2/3, 5/6, 1) alloys are investigated using density functional theory, varying atomic composition, and structure arrangements. We find WSM states in all As concentrations in SbAs alloys, with specific inversion symmetry broken. The Weyl points are located very close to the Fermi level in all compositions, facilitating their observation in experiments and suggesting that they could be characterized by analyzing surface and bulk transport properties. The presence of Fermi arcs also verifies the Weyl semimetal phase in SbAs. There is a total of 12 Weyl points located in the Brillouin zone for each composition. The chirality of these points shows that 6 Weyl points are the source and 6 Weyl points are the sink of Berry curvature. The Berry curvature calculations in these alloys align with the finding of Fermi arc results. The intrinsic spin-Hall conductivity (SHC) in SbAs alloys is in the range of 176-602 (ħ/e)(S/cm). The robust spin-orbit coupling strength and Berry curvature in these alloys produce large spin-Hall conductivity which can be used for the generation of transverse spin current for spintronic applications. Our results highlight the importance of composition and atomic arrangements for determining the Weyl semimetal phases in the SbAs alloys.