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Exactly solvable models hosting altermagnetic quantum spin liquids

João Augusto Sobral1, Pietro M. Bonetti2, Subrata Mandal1, and Mathias S. Scheurer1

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Phys. Rev. B 114, 235132 – Published 28 October, 2026

DOI: https://doi.org/10.1103/ggbl-t6d7

Abstract

We construct spin-32 and spin-72 models on the square-octagon and checkerboard lattices that are exactly solvable with Majorana representations. They give rise to spin-liquid phases with full spin-rotation and lattice-translational symmetries but broken time-reversal symmetry. Although nonzero on elementary plaquettes, the net orbital magnetic moment is guaranteed to vanish as a result of point symmetries; due to the analogy to long-range ordered altermagnets, these types of phases were dubbed altermagnetic spin liquids in [Sobral et al., Phys. Rev. Res. 7, 023152 (2025)]. For the spin-32 model, we find that a g-wave altermagnetic spin liquid emerges as the unique ground state. In contrast, the spin-72 model exhibits a significantly richer phase diagram, involving different types of chiral spin liquids competing with a d-wave altermagnetic spin liquid. Finally, we identify and characterize the topological and nontopological excitations, illustrating the rich physics of altermagnetic spin liquids resulting from the interplay of nontrivial topological and symmetry aspects of this novel phase of matter.

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Phys. Rev. B 114, 235132– Published 28 October, 2026
  • Received 3 January 2026
  • Revised 15 July 2026
  • Accepted 9 October 2026
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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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