The newly discovered Kagome superconductors AV3Sb5 (A=K, Rb and Cs) continue to bring surprises in generating unusual phenomena and physical properties, including anomalous Hall effect, unconventional charge density wave, electronic nematicity and time-reversal symmetry breaking. Here we report an unexpected emergence of multiple flat bands in the AV3Sb5 superconductors. By performing high-resolution angle-resolved photoemission (ARPES) measurements, we observed four branches of flat bands that span over the entire momentum space. The appearance of the flat bands 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. It is for the first time to observe such emergence of multiple flat bands in solid materials. Our findings provide new insights in revealing the underlying mechanism that governs the unusual behaviors in the Kagome superconductors. They also provide a new pathway in producing flat bands and set a platform to study the flat bands related physics.
@article{arxiv.2403.06085,
title = {van Hove Singularity-Driven Emergence of Multiple Flat Bands in Kagome Superconductors},
author = {Hailan Luo and Lin Zhao and Zhen Zhao and Haitao Yang and Yun-Peng Huang and Hongxiong Liu and Yuhao Gu and Feng Jin and Hao Chen and Taimin Miao and Chaohui Yin and Chengmin Shen and Xiaolin Ren and Bo Liang and Yingjie Shu and Yiwen Chen and Fengfeng Zhang and Feng Yang and Shenjin Zhang and Qinjun Peng and Hanqing Mao and Guodong Liu and Jiangping Hu and Youguo Shi and Zuyan Xu and Kun Jiang and Qingming Zhang and Ziqiang Wang and Hongjun Gao and X. J. Zhou},
journal= {arXiv preprint arXiv:2403.06085},
year = {2025}
}