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

Using density functional theory calculations, we investigated possible Weyl semimetal (WSM) phases in antimony arsenide ordered alloys Sb1-xAsx (x=0,1/6,1/3,1/2,2/3,5/6,1). We find WSM phases for all As compositions of Sb1-xAsx with broken inversion symmetry, in contrast to Bi1-xSbx where only compositions x=1/2 and 5/6 were predicted to exhibit WSM phases. The WSM phases in Sb1-xAsx are characterized by the presence of 12 Weyl points, located within 55 meV from the Fermi level in the case of x=1/2. The robust spin-orbit coupling strength and Berry curvature in these alloys produce large spin-Hall conductivity in the range of 176-602 (/e)(S/cm), comparable to that in the BiSb alloys. Finally, Sb0.5As0.5 is predicted to be almost lattice matched to GaAs(111), with the Fermi level within the gap of the semiconductor, facilitating growth and characterization, and thus, offering promising integration with conventional semiconductors.