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A topological excitonic insulator

ORAL

Abstract

We will discuss the observation of a topological excitonic insulator phase in Ta₂Pd₃Te₅, where Coulomb interactions lead to exciton formation and condensation below T = 100 K, opening a topological gap. This excitonic insulator spontaneously breaks mirror symmetries but shows minimal structural coupling, as confirmed through spectroscopy, thermodynamic, and structural analyses. Scanning tunneling microscopy reveals gapless, topological boundary modes within this bulk excitonic insulator phase. Additionally, a secondary excitonic instability occurs near T = 5 K, breaking translational symmetry. Our findings reveal two symmetry-distinct correlated topological phases in one material, offering new insights into excitonic physics and potential technological applications.

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Publication: https://arxiv.org/abs/2312.15862

Presenters

  • Shafayat Hossain

    Princeton University

Authors

  • Shafayat Hossain

    Princeton University

  • Zahid M Hasan

    Princeton University

  • Zijia Cheng

    Princeton University

  • Tyler A Cochran

    Princeton University

  • Titus M Neupert

    University of Zürich, University of Zurich, University of zurich

  • Songbo Zhang

    University of Zürich, University of Zurich

  • Xiaoxiong Liu

    University of Zurich

  • Zhiwei Wang

    Beijing Institute of Technology

  • Yuxiao Jiang

    Princeton University

  • Luis M Balicas

    National High Magnetic Field Laboratory, Florida State University, National High Magnetic Field Laboratory