Electronic states dressed by an out-of-plane supermodulation in the quasi-two-dimensional kagome superconductor <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>CsV</mml:mi><mml:mn>3</mml:mn></mml:msub><mml:msub><mml:mi>Sb</mml:mi><mml:mn>5</mml:mn></mml:msub></mml:mrow></mml:math>
Yang Luo, Shuting Peng, Samuel M. L. Teicher, Linwei Huai, Yong Hu, Yulei Han, Brenden R. Ortiz, Zuowei Liang, Zhiyuan Wei, Jianchang Shen, Zhipeng Ou, Bingqian Wang, Yu Miao, Mingyao Guo, Makoto Hashimoto, Dong-Hui Lu, Zhenhua Qiao, Zhenyu Wang, Stephen D. Wilson, Xianhui Chen, Jun-Feng He
Abstract
${\mathrm{CsV}}_{3}{\mathrm{Sb}}_{5}$ has attracted much recent attention as the first quasi-two-dimensional (2D) kagome superconductor. While the kagome layers are 2D in nature, increasing evidence has pointed to the importance of out-of-plane correlation in this material. However, it remains unclear whether such correlation can change the fundamental electronic structure of the quasi-2D system. Here, we reveal this missing piece of information, using angle-resolved photoemission spectroscopy, complemented by scanning tunneling microscope measurements. The three-dimensional electronic structures in the high-temperature state are revealed, which agree well with density-functional theory calculations. Electron energy bands are observed in the low-temperature state that exhibit additional periodicities along the out-of-plane momentum. These results reveal a direct response to the out-of-plane electronic supermodulation in the single-particle spectral function of ${\mathrm{CsV}}_{3}{\mathrm{Sb}}_{5}$, thus establishing an electronic platform to examine emergent phenomena beyond 2D limit in kagome superconductors.