Unconventional Chiral Fermions and Large Topological Fermi Arcs in RhSi

ORAL

Abstract

The theoretical proposal of chiral fermions in topological semimetals has led to a significant effort towards their experimental realization. Recent theoretical works have proposed a number of unconventional chiral fermions beyond the standard model which are protected by unique combinations of topology and crystalline symmetries. However, materials candidates for experimentally probing the transport and response signatures of these unconventional fermions have thus far remained elusive. Using first-principles electronic structure calculations, we propose the RhSi family in space group No. 198 as the ideal platform for the experimental examination of unconventional chiral fermions. We find that RhSi is a filling-enforced semimetal that features near its Fermi surface a chiral double sixfold-degenerate spin-1 Weyl node at R and a previously uncharacterized fourfold-degenerate chiral fermion at Γ. Each unconventional fermion displays |C|=4 at the Fermi level. We also show that RhSi displays the largest possible momentum separation of compensative chiral fermions, the largest proposed topologically nontrivial energy window, and the longest possible Fermi arcs on its surface. We conclude by proposing signatures of an exotic bulk photogalvanic response in RhSi.

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Presenters

  • 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

Authors

  • 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

  • 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

  • Benjamin Wieder

    Princeton University, Physics, Princeton

  • Daniel Sanchez

    Princeton Univ, Princeton University, Princeton U.

  • 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

  • Ilya Belopolski

    Princeton Univ, Princeton University, Princeton U.

  • Tay-Rong Chang

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

  • 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

  • Zahid Hasan

    Princeton Univ, Princeton University, Princeton U.