A new topological crystalline insulator state in the TaAs<sub>2</sub>materials class

ORAL

Abstract

Crystalline symmetries drive a variety of topological crystalline insulator (TCI) phases in materials. Here, based on first-principles calculations combined with associated symmetry analysis, we identify a new rotational-symmetry protected TCI state in the TaAs2family of compounds. The low-energy band structure consists of two bulk nodal lines in the absence of spin-orbit coupling (SOC) effects. Turning on the SOC opens a continuous band gap in the spectrum and drives the system into a C2Tsymmetry protected TCI state. On the (010) surface, we show the presence of rotational-symmetry-protected nontrivial Dirac cone states within a local bulk energy gap of 300 meV. Our results indicate that the TaAs2materials family provides an ideal setting for exploring unique physics associated with the rotational-symmetry protected TCIs.

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Presenters

  • Baokai Wang

    • Northeastern University
    • Physics, Northeastern University, Boston, Massachusetts 02115, USA
    • Department of Physics, Northeastern University

Authors

  • Baokai Wang

    • Northeastern University
    • Physics, Northeastern University, Boston, Massachusetts 02115, USA
    • Department of Physics, Northeastern University

  • Barun Ghosh

    • Physics, Indian Institute of Technology Kanpur,Kanpur 208016, India
    • Indian Institute of Technology Kanpur, India

  • Wei-Chi Chiu

    • Physics, Northeastern University, Boston, Massachusetts 02115, USA
    • Department of Physics, Northeastern University

  • Bahadur Singh

    • SZU-NUS Collaborative Center and International Collaborative Laboratory of 2D Materials for Optoelectronic Science & Technology, Engineering Technology Research Center for 2D
    • Department of Physics, Northeastern University, Boston, Massachusetts 02115, USA /SZU-NUS Collaborative Center and International Collaborative Laboratory of 2D Materials for
    • Department of Physics, National University of Singapore
    • SZU-NUS Collaborative Center and International Collaborative Laboratory of 2D Materials for Optoelectronic Science \& Technology, Engineering Technology Research Center for 2
    • Department of Physics, Northeastern University
    • Shenzhen University, Shenzhen, China
    • College of Optoelectronic Engineering, Shenzhen University

  • Chenliang Su

    • SZU-NUS Collaborative Center and International Collaborative Laboratory of 2D Materials for Optoelectronic Science & Technology, Engineering Technology Research Center for 2D
    • SZU-NUS Collaborative Center and International Collaborative Laboratory of 2D Materials for Optoelectronic Science \& Technology, Engineering Technology Research Center for 2
    • Shenzhen University, Shenzhen, China
    • SZU-NUS Collaborative Center and International Collaborative, Laboratory of 2D Materials for Optoelectronic Science & Technology, Engineering Technology Research Center for 2

  • Amit Agarwal

    • Physics, Indian Institute of Technology Kanpur,Kanpur 208016, India
    • Indian Institute of Technology Kanpur, India

  • Hsin Lin

    • Academia Sinica
    • Institute of Physics, Academia Sinica
    • Physics, Academia Sinica, Taipei 11529, Taiwan
    • Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
    • Physics, Academia Sinica
    • Department of Physics, National University of Singapore
    • National University of Singapore
    • Academia Sinica, Taipei, Taiwan

  • Arun Bansil

    • Department of Physics, Northeastern University
    • Northeastern
    • Physics, Northeastern University, Boston, Massachusetts 02115, USA
    • Northeastern University
    • Northeastern University, Boston (MA), USA
    • Physics, Northeastern U.
    • Department of Physics, Northwestern University
    • Physics, Northeastern University, Boston, MA, USA