2025/04/15 by Qifang Li, Qi-Fang Li, Gaopei Pan +6 · 3 citations
Physics and Astronomy · #Advanced Condensed Matter Physics
paper · doi:10.1088/0256-307x/42/5/057302
Abstract Recent various experiments have provided evidence supporting the emergence of loop-current order in kagome metals. Particularly superconductivity in AV 3 Sb 5 is significantly enhanced when this charge order is suppressed by pressure or doping. Distinct from magnetic order, loop-current order does not couple directly to spin and thus whether such fluctuations can enhance superconductivity remains elusive. We design a sign problem-free bilayer kagome model coupled to quantum Ising spins through bond currents and perform determinant quantum Monte Carlo simulations to explore single-particle properties and superconductivity arising from 2 × 2 loop-current fluctuations. We find that this loop-current order induces intriguing band folding, band broadening, and gap opening around saddle points. Remarkably, our pairing susceptibility analysis identifies a dominant enhancement of superconductivity due to loop-current fluctuations, with the dominant pairing being the chiral d -wave channel. This pairing primarily occurs within the intra-sublattice channel and involves third nearest-neighbor sites, attributed to the unique sublattice texture associated with van Hove singularities. We also discuss potential experimental implications for kagome superconductors.