近日，美国莱斯大学Yi, Ming团队报道了kagome超导体中磁场诱导动量相关对称破缺。相关论文于2026年3月11日发表在《自然—物理学》杂志上。
当量子材料中的多个自由度具有相近能量尺度时，呈现对称性破缺的交织电子序往往会产生强耦合。近期对CsV3Sb5等笼目超导体的研究报道了与电荷密度波相关的旋转对称性和时间反演对称性破缺。
研究组观测到CsV3Sb5电子结构对外部磁场的动量选择响应。通过开展可调磁场下的角度分辨光电子能谱实验，研究组证明该电子结构响应与兼具强轨道选择性的压磁效应相符。研究结果表明，时间反演对称性破缺的起源与电荷密度波序开始处的钒范霍夫奇点相关，同时研究组证实了在电荷有序温度以上仍存在涨落现象。该工作揭示出磁场可作为调控旋钮，用于在动量空间解构量子材料中的交织电子序。
附：英文原文
Title: Magnetic field-induced momentum-dependent symmetry breaking in a kagome superconductor
Author: Huang, Jianwei, Ren, Zheng, Tan, Hengxin, Hyun, Jounghoon, Zhang, Yichen, Hulse, Thomas A., Liu, Zhaoyu, DeStefano, Jonathan M., Xie, Yaofeng, Yue, Ziqin, Kono, Junichiro, Dai, Pengcheng, He, Yu, Pulkkinen, Aki, Minr, Jn, Chu, Jiun-Haw, Wang, Ziqiang, Yan, Binghai, Fernandes, Rafael M., Yi, Ming
Issue&Volume: 2026-03-11
Abstract: When several degrees of freedom in quantum materials have similar energy scales, the intertwined electronic orders, which exhibit broken symmetries, are often strongly coupled. Recent studies on kagome superconductors, such as CsV3Sb5, report rotational and time-reversal symmetry breaking linked to a charge density wave. Here we observe a momentum-selective response of the electronic structure of CsV3Sb5 to an external magnetic field. By performing angle-resolved photoemission spectroscopy in a tunable magnetic field, we demonstrate that the response of the electronic structure is compatible with piezomagnetism along with strong orbital selectivity. Our results show that the origin of the time-reversal symmetry breaking is associated with the vanadium Van Hove singularities at the onset of the charge-density-wave order. We also demonstrate the presence of fluctuations beyond the charge ordering temperature. Our results reveal that magnetic fields can be used as tuning knobs for disentangling intertwined orders in the momentum space for quantum materials.
DOI: 10.1038/s41567-026-03205-7
Source: https://www.nature.com/articles/s41567-026-03205-7