Abstract
Altermagnetic multiferroics, hosting coexisting spin-splitting bands and ferroelectric polarization, offer a promising route to magnetoelectric coupling beyond conventional relativistic spin–orbit mechanism. However, the lack of a unified principle connecting ferroelectric switching symmetry to spin-band topology has impeded rational material design. Here, we establish a universal symmetry-based framework that classifies all possible spin–ferroelectric couplings in altermagnets into three fundamental types: decoupling, pseudo-time-reversal coupling, and asymmetric momentum mapping. This classification stems directly from the relation between ferroelectric switching operators and the spin Laue group, creating a decisive symmetry-to-function paradigm. First-principles calculations on bilayer MnPS3 confirm the framework, showing that distinct ferroelectric switching paths produce characteristic spin-band reconstructions and discriminable electrical transport signatures. The universality of the framework is further validated in BiFeO3. Our work provides a predictive design principle for voltage-programmable spintronics, effectively transforming ferroelectric symmetry from a structural descriptor into a dynamic functional control knob for altermagnetic spin states.
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The relevant data generated in this study are provided in the article and Supplementary Information.
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Acknowledgements
W.S. acknowledges the support from the National Natural Science Foundation of China (Grant No. 12304141) and the Shandong Provincial Natural Science Foundation (Grant No. ZR2023QA001), W.S. and S.F.H. are grateful for the Taishan Scholars Program (Grants No. tsqn202312209 and No. tstp20221130), W.X.W. thanks the China Postdoctoral Science Foundation (Grant No. 2025M783391), S.F.H. acknowledges the Shandong provincial key research and development plan (Grant No. 2022CXPT045) and the 111 Project of International Corporation on Advanced Cement-based Materials (No. D17001). Z.X.C. thanks Australia Research Council for support (DP260102992).
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The conceptualization was carried out by W.S. and Z.X.C. Data curation was performed by W.S. and W.X.W. The visualization and original draft were completed by W.S. Formal analysis, as well as reviewing and editing the manuscript, was conducted by Z.X.C. Funding was acquired by W.S., W.X.W., S.F.H., and Z.X.C. Supervision and validation were handled by C.H.Y.
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Sun, W., Wang, W., Yang, C. et al. A unified symmetry framework for spin–ferroelectric coupling in altermagnetic multiferroics. Nat Commun (2026). https://doi.org/10.1038/s41467-026-69635-2
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DOI: https://doi.org/10.1038/s41467-026-69635-2
