Concurrent evolution of vortex phase diagram and charge density wave order in kagome superconductor CsV₃Sb_5-xSn_x

The kagome lattice superconductor CsV₃Sb₅ display a surprisingly rich vortex phase diagram, which adds to the unique properties of its superconducting state that develops from a charge density wave (CDW) state. The coexisting superconductivity and CDW in CsV₃Sb₅ can be effectively manipulated via chemical doping. Here we systematically investigate the vortex matter phases of CsV₃Sb_5-xSn_x with different doping concentrations x under in-plane magnetic fields via electrical transport, magnetic torque and ac susceptibility measurements. Three superconducting regions are identified in the phase diagrams of CsV₃Sb_5-xSn_x, corresponding to superconductivity developing from the 2×2 CDW state (x = 0, 0.06), short-ranged charge stripe state (x = 0.09) and fluctuating CDW state (x = 0.25); each is characterized by distinct behavior of vortex dynamics. The results reveal that the CDW behavior in the normal state exerts a remarkable influence on the superconducting state, which indicates unusual interplay between CDW and superconductivity in CsV₃Sb_5-xSn_x.