Type-II Symmetry-Protected Topological Dirac Semimetals

ORAL

Abstract

The recent proposal of the type-II Weyl semimetal state has attracted significant interest. In this work, we propose the concept of the three-dimensional type-II Dirac fermion and theoretically identify this new symmetry-protected topological state in the large family of VAl3 family (VAl3, Nb Al3, TaAl3, NbGa3, and TaGa3). We show that the VAl3 family features a pair of strongly Lorentz-violating type-II Dirac nodes and that each Dirac node can be split into four type-II Weyl nodes with chiral charge ±1 via symmetry breaking. Furthermore, we predict that the Landau level spectrum arising from the type-II Dirac fermions in VAl3 is distinct from that of known Dirac or Weyl semimetals. We also demonstrate a topological phase transition from a type-II Dirac semimetal to a quadratic Weyl semimetal or a topological crystalline insulator via crystalline distortions [1].

[1] T.-R. Chang et al., Phys. Rev. Lett. 119, 026404 (2017)

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Presenters

  • Tay-Rong Chang

    Physics, National Cheng Kung University, National Cheng Kung University, Department of Physics, National Tsing Hua University, Natl Cheng Kung U.

Authors

  • Tay-Rong Chang

    Physics, National Cheng Kung University, National Cheng Kung University, Department of Physics, National Tsing Hua University, Natl Cheng Kung U.

  • Suyang Xu

    MIT, Department of Physics, Massachusetts Institute of Technology, Massachusetts Institute of Technology, Princeton University, Princeton U., Massachusetts Inst of Tech-MIT

  • Daniel Sanchez

    Princeton Univ, Princeton University, Princeton U.

  • Wei-Feng Tsai

    National U. of Singapore

  • Shin-Ming Huang

    National Sun Yat-sen University, Department of Physics, National Sun Yat-sen University, National Sun Yat-Sen University, National Sun Yat-Sen U., Department of Physics, National Sun Yat-Sen University, Physic, Natl Sun Yat Sen Univ, Physics, Natl Sun Yat Sen Univ

  • Guoqing Chang

    National University of Singapore, Institute of Physics, Academica Sinica, Institute of Physics, Academia Sinica, Princeton Univ, National U. of Singapore

  • Chuang-Han Hsu

    Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, National U. of Singapore

  • Guang Bian

    Univ of Missouri - Columbia, University of Missouri, Princeton U., Department of Physics and Astronomy, University of Missouri

  • Ilya Belopolski

    Princeton Univ, Princeton University, Princeton U.

  • Zhiming Yu

    Singapore U. of Tec. and Design, Engineering Product Development Pillar, Singapore University of Technology and Design

  • Shengyuan Yang

    Singapore University of Technology and Design, Research Laboratory for Quantum Materials, Singapore University of Technology and Design, Singapore U. of Tec. and Design, Engineering Product Development Pillar, Singapore University of Technology and Design

  • Titus Neupert

    University of Zurich, Department of Physics, University of Zurich, U. of Zurich

  • Horng-Tay Jeng

    Academia Sinica, Department of Physics, National Tsing Hua University, Natl Tsing Hua Univ, National Tsing Hua University

  • Hsin Lin

    Academia Sinica, National University of Singapore, Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Institute of Physics, Academica Sinica, Institute of Physics, Academia Sinica, National U. of Singapore, Natl Univ of Singapore, National University of Signapore

  • Zahid Hasan

    Princeton Univ, Princeton University, Princeton U.