Superconducting gap evolution of kagome metal CsV3Sb5 under pressure

Kagome superconductors AV(3)Sb(5) (A=Cs, V, Sb) have served as an ideal platform to unveil the intriguing competitions between charge-density-wave (CDW), superconductivity and possible nontrivial topological states. We report soft point-contact spectroscopy (SPCS) studies on CsV3Sb5 under pressure up to 2.5 GPa. Its superconducting transition temperature T-c and gaps for SPCS at pressure P = 0.1 GPa suggest the absence of the adverse local strain effect as observed in point-contacts at ambient pressure, while the SPCS-determined T-c under hydrostatic pressure deviates from the reported double dome feature below 2.5 GPa. Three distinct gap values in CsV3Sb5 are proposed to exist through the whole pressure range with 2 delta(1)/k(B)T(c)<= 1, 2 delta(2)/k(B)T(c)similar to 2.3 -3.0 and 2 delta(3)/k(B)T(c)> 3.5. The two smaller gaps for 2 delta(1)/k(B)T(c)<= 1 and 2 & UDelta;(2)/k(B)T(c)similar to 2.3-3.0 are robust under pressure, while there is no trace of the largest gap 2 delta(3)/k(B)T(c)> 3.5 for SPCS in the c direction with P <= P-1 = 0.7 GPa and P >= P-2 = 2.0 GPa and it becomes observable in the pressure range of (P-1, P-2), suggesting a complex relation between CDW and superconductivity between (P-1, P-2).