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arXiv · 2603.12223

Persistent altermagnetism

Warlley H. Campos·F. C. Fobasso Mbognou·Anna Birk Hellenes·Joseph Poata·Taikang Chen·Jan Priessnitz·Libor Šmejkal
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Abstract

Persistent spin textures with collinear spin polarization are promising platforms for spintronics applications. However, their typically relativistic spin-orbit origin leads to weak spin splittings and fragile spin coherence. Here, we demonstrate a previously overlooked class of robust collinear spin polarization protected by mirror symmetry in combination with a strong exchange-driven altermagnetic order, which persists even in the presence of spin-orbit coupling. By combining first-principles calculations with a systematic classification of spin and magnetic layer groups, we identify this phenomenon-termed persistent altermagnetic spin polarization (PASP)-to occur in 158 spin layer groups and in representative materials including metallic V$_2$Te$_2$O, insulating La$_2$CuO$_4$, and semiconducting VSI$_2$. Furthermore, we theoretically demonstrate that PASP is ferroelectrically switchable in VSI$_2$. Finally, we show that this PASP switching can lead to large changes in spin-filtering conductance in a model all-altermagnetic junction. Our results open the possibility of employing PASP in all-altermagnetic magnetic memory and spin-transistor devices and establish universal principles of altermagnetism in spin-orbit-coupled monolayers.

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Warlley H. Campos, F. C. Fobasso Mbognou, Anna Birk Hellenes, Joseph Poata, Taikang Chen, Jan Priessnitz, Libor Šmejkal. 2026-03-12. Persistent altermagnetism. https://arxiv.org/abs/2603.12223

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