Competition between charge-density-wave and superconductivity in the kagome metal Rb V3Sb5

The interplay between charge-density-wave (CDW) order and superconductivity (SC) in the kagome metal Rb V₃Sb₅ is studied by tracking the evolutions of their transition temperatures T^* and T_c as a function of pressure (P ) via measurements of resistivity and magnetic susceptibility under various hydrostatic pressures up to ∼5 GPa. It is found that the CDW order at T^* experiences a subtle modification at P_{c 1}≈1.5 GPa before it is completely suppressed around P_{c 2}≈2.4 GPa . Accordingly, the superconducting transition T_c(P ) exhibits a shallow M-shaped double superconducting dome with two extrema of T_c^onset≈4.4 and 3.9 K around P_{c 1} and P_{c 2}, respectively, leading to a fourfold enhancement of T_c with respect to that at ambient pressure. The constructed T -P phase diagram of Rb V₃Sb₅ resembles that of Cs V₃Sb₅ and shares similar features to many other unconventional superconducting systems with intertwined competing electronic orders. The strong competition between CDW and SC is also evidenced by the broad superconducting transition width in the coexistent region. Our results shed more light on the intriguing physics involving intertwined electronic orders in this topological kagome metal family.