Topological Hopf and Chain Link Semimetal States and Their Application to Co2MnGa

ORAL

Abstract

Topological semimetals can be classified by the connectivity and dimensionality of the band crossing in momentum space. The band crossings of a Dirac, Weyl, or an unconventional fermion semimetal are 0D points, whereas the band crossings of a nodal-line semimetal are 1D closed loops. Here we propose that the presence of perpendicular crystalline mirror planes can protect 3D band crossings characterized by nontrivial links such as a Hopf link or a coupled-chain, giving rise to a variety of new types of topological semimetals. We show that the nontrivial winding number protects topological surface states distinct from those in previously known topological semimetals. We also show that these nontrivial links can be engineered by tuning the mirror eigenvalues associated with the perpendicular mirror planes. Using first-principles band structure calculations, we predict the ferromagnetic full Heusler compound Co2MnGa as a candidate. Both Hopf link and chain-like bulk band crossings and unconventional topological surface states are identified.

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Presenters

  • Daniel Multer

    Princeton Univ

Authors

  • Daniel Multer

    Princeton Univ

  • Guoqing Chang

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

  • Suyang Xu

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

  • Xiaoting Zhou

    National University 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

  • Bahadur Singh

    National University of Singapore

  • Baokai Wang

    Northeastern University, Physics, Northeastern Univ

  • Ilya Belopolski

    Princeton Univ, Princeton University, Princeton U.

  • Jiaxin Yin

    Princeton Univ

  • Songtian Sonia Zhang

    Princeton Univ, Princeton University

  • Arun Bansil

    Northeastern University, Department of Physics, Northeastern University, Northeastern Univ, Physics Department, Northeastern Univ, Physics Dept., Northeastern Univ, Physics, Northeastern 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.