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Twist-induced non-Hermitian topology of exciton–polaritons

Nature Physics volume 22, pages 151–157 (2026)Cite this article

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Abstract

Non-Hermitian physics has recently transformed our understanding of topology by uncovering a range of effects that are unique to systems with gain and loss. The realization of non-Hermitian topology in strongly coupled light–matter systems not only offers degrees of freedom for the enhanced manipulation of topological phenomena, but is also promising for developing on-chip active photonic devices. Exciton–polaritons—strongly coupled quasiparticles from excitons and photons—emerge as a promising candidate with intrinsic non-Hermitian features. However, limited by the challenges in achieving non-reciprocity, the experimental observation of non-Hermitian topology and its associated transport features has remained elusive. Here we experimentally demonstrate the non-Hermitian topology of exciton–polaritons induced by a twist degree of freedom in a liquid-crystal-filled CsPbBr3 perovskite microcavity at room temperature. The geometric twist between birefringent perovskites and liquid crystals acts as a degree of freedom to tailor the polaritonic complex spectra, leading to non-Hermitian bands with spectral winding topology and non-reciprocity. Furthermore, the induced non-Hermitian topology gives rise to the non-Hermitian exciton–polariton skin effect in real space, manifesting as polariton accumulation at open boundaries. Our findings open new perspectives on tunable non-Hermitian phenomena and the development of on-chip polaritonic devices with enhanced functionalities.

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Fig. 1: Theoretical description of non-Hermitian topologically trivial exciton–polaritons.
Fig. 2: Experimental demonstration of non-Hermitian topologically trivial exciton–polaritons.
Fig. 3: CD in twisted structures.
Fig. 4: Twist-induced non-Hermitian topological polariton bands with spectral winding.
Fig. 5: Observation of the NHSE with exciton–polaritons.

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Data availability

The data that support the plots within this Article are available via Zenodo (https://doi.org/10.5281/zenodo.17389879)60. All other data related to this study are available from the corresponding author upon request.

Code availability

The codes are available from the corresponding author upon request.

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Acknowledgements

R.S. and T.C.H.L. gratefully acknowledge funding support from the Singapore Ministry of Education via the AcRF Tier 2 grant (MOE-T2EP50222-0008), AcRF Tier 3 grant (MOE-MOET32023-0003) ‘Quantum Geometric Advantage’ and Tier 1 grant (RG80/23). R.S. also gratefully acknowledges funding support from Nanyang Technological University via a Nanyang Assistant Professorship start-up grant and the Singapore Ministry of Education via Tier 1 grant (RG 90/25). R.S. and B.Z. gratefully acknowledge funding support from the Singapore National Research Foundation via a Competitive Research Program (grant number NRF-CRP23-2019-0007). K.D. and T.C.H.L. gratefully acknowledge funding support from the Singapore National Research Foundation (NRF2023-ITC004-001). M.K. and E.A.O. acknowledge support from the Australian Research Council through the Discovery Project scheme (DP230102603). E.E. acknowledges support from the ARC Discovery Early Career Researcher Award (DE220100712).

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Author notes

  1. These authors contributed equally: Jie Liang, Hao Zheng, Feng Jin.

Authors and Affiliations

  1. Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore

    Jie Liang, Hao Zheng, Feng Jin, Ruiqi Bao, Kevin Dini, Jiahao Ren, Yuxi Liu, Baile Zhang, Timothy C. H. Liew & Rui Su

  2. Department of Quantum Science and Technology, Research School of Physics, The Australian National University, Canberra, Australian Capital Territory, Australia

    Mateusz Król, Elena A. Ostrovskaya & Eliezer Estrecho

  3. School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, Singapore

    Rui Su

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Contributions

R.S. designed the research and supervised the whole project. J.L., H.Z. and F.J. prepared the samples and conducted the optical spectroscopy measurements. H.Z. performed the modelling and theoretical calculations with inputs from T.C.H.L., R.B. and K.D. E.E., M.K. and E.A.O. developed the initial theoretical model and calculations. J.R. and Y.L. provided help on the sample fabrication. B.Z. provided valuable insight and suggestions. R.S., J.L. and H.Z. wrote the paper with the inputs from all authors.

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Correspondence to Rui Su.

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Liang, J., Zheng, H., Jin, F. et al. Twist-induced non-Hermitian topology of exciton–polaritons. Nat. Phys. 22, 151–157 (2026). https://doi.org/10.1038/s41567-025-03115-0

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