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arXiv · 2509.12802

Quintuplet condensation in the skyrmionic insulator Cu2OSeO3 at ultrahigh magnetic fields

T. Nomura·I. Rousochatzakis·O. Janson·M. Gen·X. -G. Zhou·Y. Ishii·S. Seki·Y. Kohama·Y. H. Matsuda
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Abstract

We report ultrahigh magnetic field Faraday rotation results on the chiral helimagnet Cu2OSeO3, the first Mott insulator showing skyrmion lattice phases and a linear magnetoelectric effect. Between 180 and 300 T, we find signatures of a Bose-Einstein condensation (BEC) of magnons, which can be described as a canted XY ferrimagnet. Due to the magnetoelectric coupling, the transverse magnetic order of the indivual Cu2+ spins is accompanied by a characteristic dome-like electric polarization which is crucial for the observation of the condensate via the Faraday rotation effect.

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T. Nomura, I. Rousochatzakis, O. Janson, M. Gen, X. -G. Zhou, Y. Ishii, S. Seki, Y. Kohama, Y. H. Matsuda. 2025-09-16. Quintuplet condensation in the skyrmionic insulator Cu2OSeO3 at ultrahigh magnetic fields. https://doi.org/10.1103/b6gt-w5xy

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