Novel relation between superconductivity and CDW phase in kagome metal AV₃Sb₅

Recent experiments have revealed unconventional charge density-wave (CDW) and superconductivity in frustrated kagome metal AV₃Sb₅ and their interplay attracts increasing attention. Here, we study microscopic origin of the CDW and superconductivity based on the simple Hubbard model with on-site Coulomb interaction U. We reveal that the David-Star-type bond order originates from the nonlocal backward and umklapp scattering due to the novel paramagnon interference among different van Hove singular points.  In addition, the bond-order fluctuations give sizable beyond-Migdal pairing interaction for superconductivity. For this reason, both the triplet p-wave pairing and the singlet s-wave pairing states are expected to emerge as bond-fluctuation mediated exotic superconducting phase.