Prediction and control of spin polarization in a Weyl semimetallic phase of BiSb

Abstract

Recent experimental realization of long sought Weyl fermions in non-magnetic crystals has greatly motivated condensed matter physicists to search for materials supporting Weyl fermions. Weyl fermions appear to be very promising for future electronics, often referred as Weyltronics. Here, by means of first-principle calculations, we report a stoichiometric crystal structure of BiSb with broken space-inversion symmetry. This structure is insulating in bulk and has non-trivial band topology. We observe a pressure driven Weyl semi-metallic phase transition in this crystal structure. The obtained Weyl semi-metallic phase exists in the 4.0 - 6.0 GPa pressure range. We find that a total 6 pairs of Weyl points, 6 monopoles and 6 antimonopoles, exist in the Brillouin zone. The Weyl points with opposite chirality are located at different energy values yielding separate electron and hole Fermi-surfaces. Additionally, the spin-texture of the bulk BiSb compound appears to be electrically controllable when the interlink between pressure and an electric field is exploited. This produces novel manipulable topological transport properties in this system which are very promising for implementation of this kind of materials in next-generation Weyltronics and spintronic devices.