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

Abstract

Recently synthesized Kagome compounds AV3Sb5 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 CsV3Sb5 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 AV3Sb5 is weak or intermediate, these results suggest that pairing symmetry is A 2 g (I-wave) in the CsV3Sb5, which can explain some recent experiments about pairing symmetry.