(TaSe4)<sub>2</sub>I: A Charge-Density-Wave Topological Semimetal

ORAL

Abstract

Topological physics and strong electron-electron correlations in quantum materials are typically studied independently. However, there have been rapid recent developments in quantum materials in which topological phase transitions emerge when the single-particle band structure is modified by strong interactions. In [Shi*, Wieder*, Meyerheim*, et al., Nat. Phys. (2021)], we demonstrate that the room-temperature phase of (TaSe4)2I is a Weyl semimetal with 24 pairs of Weyl nodes. Owing to its quasi-1D structure, (TaSe4)2I hosts an established CDW instability just below room temperature. Using X-ray diffraction, angle-resolved photoemission spectroscopy, and first-principles calculations, we find that the CDW in (TaSe4)2I couples the bulk Weyl points and opens a band gap. The correlation-driven topological phase transition in (TaSe4)2I provides a route towards observing condensed-matter realizations of axion electrodynamics in the gapped regime, topological chiral response effects in the semimetallic phase, and represents an avenue for exploring the interplay of correlations and topology in a solid-state material.

*DOE Grant No. DE-SC0016239
Simons Investigator Grant No. 404513
ONR Grant No. N00014-20-1-2303
the National Natural Science Foundation of China [Grant No. 11974395]

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Presenters

  • Zhijun Wang

    • Princeton University, Department of Physics
    • Chinese Academy of Sciences, Institute of Physics
    • Institute of Physics, Chinese Academy of Sciences
    • Chinese Academy of Sciences,Institute of Physics

Authors

  • Wujun Shi

    • School of Physical Science and Technology, ShanghaiTech University

  • Benjamin J. Wieder

    • Department of Physics, Massachusetts Institute of Technology
    • Massachusetts Institute of Technology

  • Holger L. Meyerheim

    • Max Planck Institute of Microstructure Physics

  • Yan Sun

    • Max Planck Institute for Chemical Physics of Solids
    • Max Planck, Dresden
    • Max Planck Institute for Chemical Physics of Solids, 01187 Dresden

  • Yulin Chen

    • School of Physical Science and Technology, ShanghaiTech University
    • Department of Physics, University of Oxford
    • University of Oxford
    • Unviersity of Oxford

  • Claudia Felser

    • Max Planck Institute for Chemical Physics of Solids
    • Max Planck Institute for the Chemical Physics of Solids
    • Solid State Chemistry, Max Planck Institute for Chemical Physics of Solids
    • Max Planck Institute, Dresden, Germany
    • Max Planck, Dresden
    • Max Planck Institute for Chemical Physics of Solids, 01187 Dresden
    • Max Planck Institute for Chemical Physics of Solids,

  • Andrei Bernevig

    • Princeton University
    • Department of Physics, Princeton University
    • Physics, Princeton University

  • Zhijun Wang

    • Princeton University, Department of Physics
    • Chinese Academy of Sciences, Institute of Physics
    • Institute of Physics, Chinese Academy of Sciences
    • Chinese Academy of Sciences,Institute of Physics