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Distinct topological excitonic insulators characterized by quantum geometry

Zhuowei Liu1, Rui Wang2,3,4,5,*, and Baigeng Wang2,3,4,†

  • *Contact author: rwang89@nju.edu.cn
  • †Contact author: bgwang@nju.edu.cn
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Phys. Rev. Research 7, 043207 – Published 21 November, 2025

DOI: https://doi.org/10.1103/18dk-tr69

Abstract

The intertwining of electron-hole correlation and nontrivial topology is known to give rise to exotic topological excitonic insulators. Here, we show that the involvement of quantum geometry can characterize more exotic excitonic phases exhibiting physical properties that are not influenced by their topology but by geometry. Starting from a topological band insulator and gradually reducing the band gap, many-body interaction can initially generate a p+ip-wave and then an s-wave excitonic insulator. Interestingly, they bear the same Chern number but exhibit completely different spin textures and magneto-optical Kerr responses, reflecting the intricate geometric distinctions in their wave functions. We also propose to enhance the correlation effect via Floquet engineering, which provides a systematic way to realize these topological excitonic insulators and their phase transitions in the nonequilibrium steady states. Our results demonstrate correlated phenomena characterized by quantum geometry, beyond the conventional topological classifications.

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Phys. Rev. Research 7, 043207– Published 21 November, 2025
  • Received 18 September 2024
  • Accepted 19 October 2025
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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