スピン四量体で初めてマグノンのボース−アインシュタイン凝縮を発見 ―スキルミオン物質に潜む未知の超強磁場物性を明らかに―

2026-02-24 静岡大学

＜関連情報＞

• https://www.shizuoka.ac.jp/news/detail.html?CN=11664
• https://journals.aps.org/prl/abstract/10.1103/b6gt-w5xy

スカイミオン絶縁体における五重項凝縮Cu2⁢OSeO3超高磁場において Quintuplet Condensation in the Skyrmionic Insulator Cu2⁢OSeO3 at Ultrahigh Magnetic Fields

T. Nomura, I. Rousochatzakis, O. Janson, M. Gen, X.-G. Zhou, Y. Ishii, S. Seki Y. Kohama, and Y. H. Matsuda
Physical Review Letters  Published: 19 February, 2026
DOI: https://doi.org/10.1103/b6gt-w5xy

Abstract

We report ultrahigh magnetic field Faraday rotation results on the chiral helimagnet Cu₂⁢OSeO₃, 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 of magnons, which can be described as a canted XY ferrimagnet. Because of the magnetoelectric coupling, the transverse magnetic order of the individual Cu²⁺ spins is accompanied by a characteristic domelike electric polarization which is crucial for the observation of the condensate via the Faraday rotation effect.