Small Fermi Pockets Intertwined with Charge Stripes and Pair Density Wave Order in a Kagome Superconductor
Hong Li, Dongjin Oh, Mingu Kang, He Zhao, Brenden R. Ortiz, Yuzki M. Oey, Shiang Fang, Zheng Ren, Chris Jozwiak, Aaron Bostwick, Eli Rotenberg, J. G. Checkelsky, Ziqiang Wang, Stephen D. Wilson, Riccardo Comin, Ilija Zeljkovic
Abstract
The kagome superconductor family AV_{3}Sb_{5} (A=Cs, K, Rb) emerged as an exciting platform to study exotic Fermi surface instabilities. Here, we use spectroscopic-imaging scanning tunneling microscopy (SI-STM) and angle-resolved photoemission spectroscopy (ARPES) to reveal how the surprising cascade of higher- and lower-dimensional density waves in CsV_{3}Sb_{5} is intimately tied to a set of small reconstructed Fermi pockets. ARPES measurements visualize the formation of these pockets generated by a 3D charge density wave transition. The pockets are connected by dispersive q^{*} wave vectors observed in Fourier transforms of STM differential conductance maps. As the additional 1D charge order emerges at a lower temperature, q^{*} wave vectors become substantially renormalized, signaling further reconstruction of the Fermi pockets. Remarkably, in the superconducting state, the superconducting gap modulations give rise to an in-plane Cooper pair density wave at the same q^{*} wave vectors. Our work demonstrates the intrinsic origin of the charge stripes and the pair density wave in CsV_{3}Sb_{5} and their relationship to the Fermi pockets. These experiments uncover a unique scenario of how Fermi pockets generated by a parent charge density wave state can provide a favorable platform for the emergence of additional density waves.