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 $E_{1u}$ ( p wave) pairing dominates in the region of $0\lt U\lt0.32$ eV, the $A_{2g}$ ( I wave) in the region of $0.32\lt U\lt0.75$ eV and the $E_{2g}$ ( d wave) in the region of $0.75\lt U\lt1$ eV. Considering that the correlation in AV _3 Sb _5 is weak or intermediate, these results suggest that pairing symmetry is $A_{2g}$ ( I -wave) in the CsV _3 Sb _5 , which can explain some recent experiments about pairing symmetry.

Keywords

• Kagome superconductor
• pairing mechanism
• spin fluctuations
• I-wave pairing