Rotation symmetry breaking in the normal state of a kagome superconductor KV3Sb5
Rotation symmetry breaking in the normal state of a kagome superconductor KV3Sb5
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DOI：
10.1038/s41567-021-01479-7
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发表时间：
2022-01-20
期刊：
影响因子：
19.6
通讯作者：
Zeljkovic, Ilija
中科院分区：
文献类型：
--
作者：
Li, Hong;Zhao, He;Zeljkovic, Ilija
最近发现的超导体 AV(3)Sb(5) (A = K, Rb, Cs)(1,2) 为研究 kagome 晶格上相关驱动的电子现象提供了新的机会。在 AV(3)Sb(5) 家族 (2-10) 所有成员的正常状态下观察到的异常电荷密度波 (CDW) 促使人们付出巨大努力来识别与其相关的任何“隐藏”对称性破缺。我们使用光谱成像扫描隧道显微镜揭示了 KV3Sb5 中六方 CDW 不同方向之间明显的强度各向异性。特别是，我们发现 CDW 方向之一与其他两个方向明显不同。这一观察结果指出了一种固有的旋转对称性破缺的电子基态，其中对称性从六倍降低到两倍。此外，与之前的报道(3)相反，我们发现无论是否存在原子缺陷，CDW相对磁场方向不敏感。我们的实验结合早期对 CsV3Sb5 中条带电荷排序的观察，建立了相关驱动的旋转对称性破缺作为 AV(3)Sb(5) kagome 超导体的统一特征。
Recently discovered superconductors AV(3)Sb(5) (A = K, Rb, Cs)(1,2) provide a fresh opportunity to study correlation-driven electronic phenomena on a kagome lattice. The observation of an unusual charge density wave (CDW) in the normal state of all the members of the AV(3)Sb(5) family(2-10) has prompted a large effort to identify any 'hidden' broken symmetries associated with it. We use spectroscopic-imaging scanning tunnelling microscopy to reveal pronounced intensity anisotropy between the different directions of hexagonal CDW in KV3Sb5. In particular, we find that one of the CDW directions is distinctly different compared with the other two. This observation points to an intrinsic rotation-symmetry-broken electronic ground state where the symmetry is reduced from sixfold to twofold. Furthermore, in contrast to previous reports(3), we find that the CDW phase is insensitive to the magnetic-field direction, regardless of the presence or absence of atomic defects. Our experiments, combined with earlier observations of stripe charge ordering in CsV3Sb5, establish correlation-driven rotation symmetry breaking as a unifying feature of AV(3)Sb(5) kagome superconductors.