Electronic nature of charge density wave and electron-phonon coupling in kagome superconductor KV3Sb5

• Published in: Nature communications Vol. 13; no. 1; pp. 273 - 8
• Main Authors: Luo, Hailan, Gao, Qiang, Liu, Hongxiong, Gu, Yuhao, Wu, Dingsong, Yi, Changjiang, Jia, Junjie, Wu, Shilong, Luo, Xiangyu, Xu, Yu, Zhao, Lin, Wang, Qingyan, Mao, Hanqing, Liu, Guodong, Zhu, Zhihai, Shi, Youguo, Jiang, Kun, Hu, Jiangping, Xu, Zuyan, Zhou, X. J.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 12.01.2022; Nature Publishing Group; Nature Portfolio
• Subjects: 639/301/119/1003; 639/766/119/2795; 639/766/119/995; Anisotropy; Brillouin zones; Charge density waves; Coupling; Crystal structure; Electronic structure; Electrons; Fermi surfaces; Humanities and Social Sciences; Laboratories; multidisciplinary; Phase transitions; Phonons; Photoelectric emission; Physical properties; Physics; Reconstruction; Science; Science (multidisciplinary); Signatures; Superconductivity; Superconductors; Symmetry
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-27946-6

The Kagome superconductors AV 3 Sb 5 (A = K, Rb, Cs) have received enormous attention due to their nontrivial topological electronic structure, anomalous physical properties and superconductivity. Unconventional charge density wave (CDW) has been detected in AV 3 Sb 5 . High-precision electronic structure determination is essential to understand its origin. Here we unveil electronic nature of the CDW phase in our high-resolution angle-resolved photoemission measurements on KV 3 Sb 5 . We have observed CDW-induced Fermi surface reconstruction and the associated band folding. The CDW-induced band splitting and the associated gap opening have been revealed at the boundary of the pristine and reconstructed Brillouin zones. The Fermi surface- and momentum-dependent CDW gap is measured and the strongly anisotropic CDW gap is observed for all the V-derived Fermi surface. In particular, we have observed signatures of the electron-phonon coupling in KV 3 Sb 5 . These results provide key insights in understanding the nature of the CDW state and its interplay with superconductivity in AV 3 Sb 5 superconductors. The impact of the charge density wave (CDW) state to the electronic structure in the Kagome superconductors A V 3 Sb 5 remains unclear. Here, the authors observe CDW-induced Fermi surface reconstruction with a strongly anisotropic CDW gap and signatures of the electron-phonon coupling for all V-derived bands.