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

TL;DR

This study uses density functional theory to identify Weyl semimetal phases and high spin-Hall conductivity in SbAs alloys, highlighting their potential for integration with semiconductors like GaAs.

Contribution

It reveals that all Sb1-xAsx compositions with broken inversion symmetry host Weyl semimetal phases, expanding the understanding of topological phases in these alloys.

Findings

Weyl semimetal phases found in all Sb1-xAsx compositions with broken inversion symmetry.

Presence of 12 Weyl points near the Fermi level in x=1/2 composition.

Large spin-Hall conductivity comparable to BiSb alloys.

Abstract

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 (hbar/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.