カゴメ金属で隠れた相転移を発見――電子の「電荷」と「スピン」が別々に整列――

2026-07-17 東京大学,京都大学,名古屋大学

カゴメ格子（右）で現れた、電荷とスピンの二段階の電子秩序のイメージ図

＜関連情報＞

• https://www.k.u-tokyo.ac.jp/information/category/press/0030274.html
• https://www.nature.com/articles/s41467-026-74096-8

カゴメ金属CsCr3Sb 5における電荷スピン二分法 Charge-spin dichotomy in the kagome metal CsCr3Sb5

Asato Onishi,Yoichi Kageyama,Cédric Bareille,Sogen Ikegami,Zifan Xu,Kota Ishihara,Hirokazu Fujiwara,Zehao Wang,Bin Gao,Weiliang Yao,Pengcheng Dai,Youichi Yamakawa,Hiroshi Kontani,Toshiyuki Taniuchi,Kenichiro Hashimoto & Takasada Shibauchi
Nature Communications  Published:17 July 2026
DOI:https://doi.org/10.1038/s41467-026-74096-8

Abstract

Kagome metals host a variety of correlated electronic states, yet the nature of their intertwined orders remains an open question. The recently discovered Cr-based kagome compound CsCr₃Sb₅ differs from its V-based analogue CsV₃Sb₅ by exhibiting stronger correlations and a magnetic ground state. While multiple broken symmetries have been reported in CsV₃Sb₅, only a single transition at T^* ≈ 55 K has been identified at ambient pressure in CsCr₃Sb₅, with its origin unresolved. Here we uncover an additional phase transition above T^* through elastoresistivity measurements. Rotational symmetry breaking without divergent nematic susceptibility is identified around T ≈ 64 K, which is most consistently explained as the emergence of charge-density-wave order. Laser-based photoemission-electron microscopy further reveals three-domain structures associated with spin-density-wave order below T^*. These findings indicate distinct charge and spin order transitions in CsCr₃Sb₅, offering crucial insight into the intertwined orders and pressure-induced superconductivity in this system.