Effective six-band model and unconventional spin-singlet pairing in Kagome superconductor CsV3Sb5

Abstract Recently synthesized Kagome compounds AV 3 Sb 5 attract great attention due to the unusual coexistence of the topology, charge density wave, and superconductivity. In this work, based on the band structures for CsV 3 Sb 5 in the pristine phase, we construct an effective six-band model for the low-energy processes; utilizing the random phase approximation on the effective six-band model, we show that the E 1 u ( p wave) pairing dominates in the region of 0 < U < 0.32 eV, the A 2 g ( I wave) in the region of 0.32 < U < 0.75 eV and the E 2 g ( d wave) in the region of 0.75 < U < 1 eV. Considering that the correlation in AV 3 Sb 5 is weak or intermediate, these results suggest that pairing symmetry is A 2 g ( I -wave) in the CsV 3 Sb 5 , which can explain some recent experiments about pairing symmetry.