g-Tensors and Band Structure Evolution of BiSb Alloys under Magnetic Field

ORAL

Abstract

Bi and Sb alloys exhibit novel physical phenomena depending on the antimony concentration, such as semimetal-semiconductor transitions, giant spin Hall conductivities, and topologically protected phases including Weyl semimetal phases. Although the band structures of Bi and Sb are well studied in terms of k.p or tight-binding Hamiltonians, it is still a challenge to predict the behavior of the band edges as a function of the alloy concentration. Simple linear virtual crystal approximations lack the correct symmetries of the electron and hole pockets; on the other hand, alternative VCA approaches are insufficient to describe band crossings at different Sb concentrations. In this work, we introduce a new VCA parametrization describing the symmetries and crossing of the band edges using a 16 band tight-binding Hamiltonian. Then, from that Hamiltonian, we derive and calculate g-tensors of the electrons and holes and show that the large spin-orbit couplings of Bi and Sb result in giant effective g-factors whose axes of symmetry differ from the crystallographic axes. We also show that the band gap between symmetric and antisymmetric bands at the L point can be closed by a moderate magnetic field due to large g-factors. The closing of this gap produces a Weyl state.

*NSF DMR-1420451

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Presenters

  • Cuneyt Sahin

    • Physics and Astronomy, University of Iowa, Iowa City
    • Department of Physics and Astronomy, University of Iowa
    • Optical Science and Technology Center and Department of Physics and Astronomy, University of Iowa

Authors

  • Cuneyt Sahin

    • Physics and Astronomy, University of Iowa, Iowa City
    • Department of Physics and Astronomy, University of Iowa
    • Optical Science and Technology Center and Department of Physics and Astronomy, University of Iowa

  • Dung Vu

    • Department of Mechanical Engineering, The Ohio State University
    • Department of Mechanical and Aerospace Engineering, The Ohio State University

  • WENJUAN ZHANG

    • Department of Physics, The Ohio State University
    • Department of Physics, Ohio State University

  • Nandini Trivedi

    • Ohio State University
    • Department of Physics, The Ohio State University
    • Department of Physics, Ohio State University
    • The Ohio State University
    • Physics, Ohio State University

  • Joseph P C Heremans

    • Department of Mechanical and Aerospace Engineering, The Ohio State University
    • Ohio State University
    • Ohio State Univ - Columbus
    • Department of Mechanical Engineering, The Ohio State University
    • Department of Mechanical and Aerospace Engineering, Department of Physics, Department of Materials Science and Engineering, The Ohio State University, Columbus, OH 43210, USA

  • Michael Flatté

    • Optical Science and Technology Center and Department of Physics and Astronomy, University of Iowa
    • Department of Physics and Astronomy and Optical Science and Technology Center, University of Iowa
    • Physics and Astronomy, University of Iowa, Iowa City
    • University of Iowa
    • Department of Physics and Astronomy, University of Iowa
    • Physics and Astronomy, University of Iowa