Anisotropic Superconducting Properties of Kagome Metal CsV_3Sb_5

We systematically measure the superconducting (SC) and mixed state properties of high-quality CsV_3Sb_5 single crystals with T_\rm c \sim 3.5 K. We find that the upper critical field H_\rm c2(T) exhibits a large anisotropic ratio of H_\rm c2^ab/H_\rm c2^c \sim 9 at zero temperature and fitting its temperature dependence requires a minimum two-band effective model. Moreover, the ratio of the lower critical field, H_\rm c1^ab/H_\rm c1^c, is also found to be larger than 1, which indicates that the in-plane energy dispersion is strongly renormalized near Fermi energy. Both H_\rm c1(T) and SC diamagnetic signal are found to change little initially below T_\rm c \sim 3.5 K and then to increase abruptly upon cooling to a characteristic temperature of \sim 2.8 K. Furthermore, we identify a two-fold anisotropy of in-plane angular-dependent magnetoresistance in the mixed state. Interestingly, we find that, below the same characteristic T \sim 2.8 K, the orientation of this two-fold anisotropy displays a peculiar twist by an angle of 60^\circ characteristic of the Kagome geometry. Our results suggest an intriguing superconducting state emerging in the complex environment of Kagome lattice, which, at least, is partially driven by electron-electron correlation.