カゴメ金属の特異なホール効果の起源を解明～移動度スペクトル解析で捉えた高移動度キャリアの役割～

2025-08-06 東京大学,東北大学,日本原子力研究開発機構

カゴメ金属における移動度スペクトル解析

＜関連情報＞

• https://www.k.u-tokyo.ac.jp/information/category/press/11702.html
• https://www.k.u-tokyo.ac.jp/information/upload/62f75fb8b4d86aa70df7bdd4abbab4796bf64695.pdf
• https://journals.aps.org/prl/abstract/10.1103/d4dw-2v6k

カゴメ金属CsV3Sb5における極小フェルミポケットと極高移動度によるホール異常への影響 Impact of Tiny Fermi Pockets with Extremely High Mobility on the Hall Anomaly in the Kagome Metal CsV3⁢Sb5

S. Liu, M. Roppongi, M. Kimata, K. Ishihara, R. Grasset, M. Konczykowski, B. R. Ortiz, S. D. Wilson, K. Yoshimi et al.
Physical Review Letters  Published: 30 July, 2025
DOI: https://doi.org/10.1103/d4dw-2v6k

Abstract

The kagome metal CsV₃⁢Sb₅ exhibits an unusual charge-density-wave (CDW) order, where the emergence of loop current order that breaks time-reversal symmetry (TRS) has been proposed. A key feature of this CDW phase is a nonmonotonic Hall effect at low fields, often attributed to TRS breaking. However, its origin remains unclear. Here, we conduct comprehensive magnetotransport measurements on CsV₃⁢Sb₅ and, through mobility spectrum analysis, identify the formation of tiny Fermi pockets with extremely high mobility below the CDW transition. Furthermore, electron irradiation experiments reveal that the nonmonotonic Hall effect is significantly suppressed in samples with reduced mobility, despite no substantial change in the electronic structure. These results indicate that the nonmonotonic Hall effect originates from these tiny Fermi pockets with high mobility carriers rather than anomalous Hall mechanisms, providing new insights into understanding the Hall anomaly in this kagome system.