Competition of superconductivity and charge density wave in selective oxidized CsV₃Sb₅ thin akes

The recently discovered layered kagome metals AV3Sb5 (A = K, Rb, and Cs) with vanadium kagome networks provide a novel platform to explore correlated quantum states intertwined with topological band structures. In the firt part, we report the prominent eect of hole doping on both superconductivity and charge density wave (CDW) order, achieved by selective oxidation of exfoliated thin akes. A superconducting dome is revealed as a function of the effective doping content. The superconducting transition temperature (Tc) and upper critical eld in thin akes are significantly enhanced compared with the bulk, which are accompanied by the suppression of CDW. Our detailed analyses establish the pivotal role of van Hove singularities (VHSs) in promoting correlated quantum orders in these kagome metals. Our experiment not only demonstrates the intriguing nature of superconducting and CDW orders, but also provides a novel route to tune the carrier concentration through both selective oxidation and electric gating. In the second part, we report our discovery of two new families of A-V-Sb system, namely AV6Sb6 and AV8Sb12.