Van Hove singularity driven emergence of multiple flat band-like nondispersive features in kagome superconductors

作者：Hailan Luo, Lin Zhao, Zhen Zhao, Haitao Yang, Yun-Peng Huang, Hongxiong Liu, Yuhao Gu, Feng Jin, Hao Chen, Taimin Miao, Chaohui Yin, Chengmin Shen, Xiaolin Ren, Bo Liang, Yingjie Shu, Yiwen Chen, Fengfeng Zhang, Feng Yang, Shenjin Zhang, Qinjun Peng, Hanqing Mao, Guodong Liu, Jiangping Hu, Youguo Shi, Zuyan Xu, Kun Jiang, Qingming Zhang, Ziqiang Wang, Hongjun Gao, Xingjiang Zhou · 发表于：Physical review. B./Physical review. B · 年份：2025 · DOI：10.1103/physrevb.111.155123 · 被引用次数：4 · 研究领域：Advanced Condensed Matter Physics、Physics of Superconductivity and Magnetism、Topological Materials and Phenomena

The newly discovered kagome superconductors $A{\mathrm{V}}_{3}{\mathrm{Sb}}_{5}$ ($A$ = K, Rb, and Cs) continue to bring surprises in generating unusual phenomena and physical properties, including the anomalous Hall effect, unconventional charge density wave, electronic nematicity, and time-reversal symmetry breaking. Here we report an unexpected emergence of multiple flat band-like nondispersive features in the $A{\mathrm{V}}_{3}{\mathrm{Sb}}_{5}$ superconductors. By performing high-resolution angle-resolved photoemission (ARPES) measurements, we observed four branches of nondispersive features that span over the entire momentum space. The appearance of the nondispersive features is not anticipated from the band structure calculations and cannot be accounted for by the known mechanisms of flat band generation. It is intimately related to the evolution of Van Hove singularities. Here we observe such emergence of multiple nondispersive features in solid materials. Our findings provide insights in revealing the underlying mechanism that governs the unusual behaviors in the kagome superconductors. They also provide a pathway in producing nondispersive features and set a platform to study flat band related physics.