Two-fold symmetry of the in-plane resistance in kagome superconductor Cs(V_1–xTa_x)₃Sb₅ with enhanced superconductivity

The kagome superconductor CsV₃Sb₅ has attracted widespread attention due to its rich correlated electron states including superconductivity, charge density wave (CDW), nematicity, and pair density wave. Notably, the modulation of the intertwined electronic orders by the chemical doping is significant to illuminate the cooperation/competition between multiple phases in kagome superconductors. In this study, we have synthesized a series of tantalum-substituted Cs(V_1−xTa_x)₃Sb₅ by a modified self-flux method. Electrical transport measurements reveal that CDW is suppressed gradually and becomes undetectable as the doping content of x is over 0.07. Concurrently, the superconductivity is enhanced monotonically from T_c ∼ 2.8 K at x = 0 to 5.2 K at x = 0.12. Intriguingly, in the absence of CDW, Cs(V_1−xTa_x)₃Sb₅ (x = 0.12) crystals exhibit a pronounced two-fold symmetry of the in-plane angular-dependent magnetoresistance (AMR) in the superconducting state, indicating the anisotropic superconducting properties in the Cs(V_1−xTa_x)₃Sb₅. Our findings demonstrate that Cs(V_1−xTa_x)₃Sb₅ with the non-trivial band topology is an excellent platform to explore the superconductivity mechanism and intertwined electronic orders in quantum materials.