Regulation of charge density wave and superconductivity in kagome superconductor CsV3Sb5 by intercalation

AV₃Sb₅ (A ​= ​K, Rb, and Cs), recently discovered van der Waals Kagome metals, exhibit a multitude of intriguing strongly correlated phenomena, particularly the unconventional charge density wave (CDW) and superconductivity, and thus have generated tremendous attention. In this study, we modulated CDW orders and superconductivity in CsV₃Sb₅ flakes utilizing an ionic-gel electrolyte (LiClO₄/PEO), which also serves as a protective layer to prevent the CsV₃Sb₅ thin flakes from being degraded in air. The dominated carriers of pristine CsV₃Sb₅ undergoes a transition from electron-type above 50 ​K to hole-type below 10 ​K, while both electron and hole carriers participate in the transport process at 25 ​K. The CDW transition temperature increases (from 86 ​K up to 106 ​K) and behaves a positive correlation with the electron-type carrier concentration, while the superconducting transition temperature decreases and behaves a negative correlation with the hole-type carrier concentration. The regulation of carrier density induces a shift in the relative positions of Fermi level and van Hove singularities, leading to the modulation of CDW order and superconductivity. Our work demonstrates CsV₃Sb₅ as a versatile platform for tuning CDW order and superconductivity, and provides valuable insights into the physical properties of Kagome metals.