Chiral Superconductivity from Loop-Current Chern Metal in Kagome Superconductor AV3Sb5 (A=K,Rb,Cs)

Recently, extensive study on the Kagome metals and superconductors AV3Sb5 (A=K,Rb,Cs) have revealed fascinating correlated quantum states. Central to the discovery is the evidence for Time-Reversal Symmetry (TRS) breaking in both the Charge Density Wave (CDW) metal state and the superconducting state. In this work, we study the superconducting state derived from the loop-current CDW metal. The loop current CDW was proposed to account for evidence of TRS breaking and has features in good agreement with experimental observations of small Fermi pockets. Here we carry out instability analysis in the pairing channel using Ginzburg-Landau theory and found loop current drive a chiral topological superconductor. The physical reason behind the TRS breaking pairing is attributed to the complex Josephson scattering among Fermi pockets induced by loop current. The results are further confirmed through self-consistent mean-field calculation.