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arXiv · 2602.11983

Dynamics and thermodynamics of the S = 5/2 almost Heisenberg triangular lattice antiferromagnet K2Mn(SeO3)2

Mengze Zhu·V. Romerio·D. Moser·K. Yu. Povarov·R. Sibille·R. Wawrzynczak·Z. Yan·S. Gvasaliya·A. L. Chernyshev·A. Zheludev
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Abstract

We report calorimetric, magnetic, and neutron scattering studies on an S = 5/2, nearly Heisenberg triangular-lattice antiferromagnet K2Mn(SeO3)2 with weak XXZ easy-axis anisotropy. Multiple magnetic phases are identified, including a non-collinear Y phase in zero field, a field-induced collinear m = 1/3 magnetization plateau, and a high-field V phase. In the Y phase, the magnetic excitation spectrum exhibits both single-magnon excitations and an extended high-energy continuum. Both features are well described by non-linear spin wave theory. In the field-induced phases, complex effects of the spectrum renormalization even for large S = 5/2 material are clearly detectable. These results underscore the essential role of magnon-magnon interactions in the dynamics of large-S Heisenberg spin systems on a triangular lattice.

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Mengze Zhu, V. Romerio, D. Moser, K. Yu. Povarov, R. Sibille, R. Wawrzynczak, Z. Yan, S. Gvasaliya, A. L. Chernyshev, A. Zheludev. 2026-02-12. Dynamics and thermodynamics of the S = 5/2 almost Heisenberg triangular lattice antiferromagnet K2Mn(SeO3)2. https://doi.org/10.1103/slnw-rkw3

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