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Multiple types of van Hove singularities induced by band inversion

ORAL

Abstract

Saddle-point Van Hove singularities in the electron density of states can cause system instabilities that lead to exotic phases of matter. Here, we show that such singularities are very common near the Fermi level of topological semimetals and insulators. Using a k.p model analysis, we find that multiple types of saddle points with different divergence behaviors can be induced by band inversion. In particular, we uncover a new type of saddle-like dispersion (called “saddle line”) that significantly enhances the divergence in the density of states. We present examples of ab initio electron band structures of topological materials including monolayer 1T’-WS2, monolayer decorated stanene, and Dirac semimetal Na3Bi. Our results suggest a new universal property of topological materials that can lead to further opportunities.

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Presenters

  • Jiawei Ruan

    Nanjing University, University of California at Berkeley, and Lawrence Berkeley National Laboratory

Authors

  • Jiawei Ruan

    Nanjing University, University of California at Berkeley, and Lawrence Berkeley National Laboratory

  • Huaiqiang Wang

    Physics, Nanjing University

  • Steven Louie

    University of California at Berkeley, and Lawrence Berkeley National Laboratory, Department of Physics, University of California, Berkeley, Berkeley, California 94720, USA and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, C, University of California, Berkeley, Department of Physics, University of California, Berkeley, Lawrence Berkeley National Laboratory and University of California at Berkeley, Department of Physics, University of California at Berkeley and Lawrence Berkeley National Laboratory, Department of Physics, UC Berkeley, Physics, Unviersyt of Calfornia, Berkeley, Physics, University of California, Berkeley, Physics, University of California, Berkeley and Lawrence Berkeley National Lab

  • Hai-Jun Zhang

    Physics, Nanjing University