Mechanism for loop current order in kagome metals AV3Sb5 from intertwined van-Hove singularities

Recent studies on kagome metals AV3Sb5 (A=Cs, Rb, K) have revealed charge density wave with spontaneous time-reversal symmetry breaking, suggesting the loop current order (LCO) as a candidate phase. In our work, we demonstrate that coupling between van-Hove singularities (vHS) with different mirror symmetries plays a crucial role in stabilizing an LCO ground state. Through an effective model, we show that when vHS with distinct mirror eigenvalues are close in energy, nearest-neighbor electron repulsion leads to a ground state featuring both LCO and charge bond order. This mechanism is applicable to kagome metals AV3Sb5, offering new insights into the origin of LCO and advancing our understanding of the complex quantum behaviors in kagome systems.