The exotic electronic states in the charge loop current (cLC) phase, in which the permanent charge current breaks the time-reversal symmetry, have been attracting increasing attention in recently discovered kagome metals AV₃⁢Sb₅ (A=Cs,Rb,K). Interestingly, the cLC state is sensitively controlled by applying a small magnetic field as well as a tiny uniaxial strain. In addition, many experiments indicate that the cLC state is sensitive to the small number of impurities. To understand the impurity effects on the cLC electronic states accurately, we analyze the giant unit-cell (up to 1200 sites) kagome lattice model with single impurity potential. The loop current is found to be strongly suppressed within the current correlation length ξ_J centered on the impurity site, where ξ_J increases as the cLC order parameter η decreases. (The cLC order is the pure imaginary hopping integral modulation δ⁢t_i,j = ±iη.) In addition, both the uniform orbital magnetization M_orb and the anomalous Hall conductivity σ_xy are drastically suppressed by dilute impurities. Especially, the suppression ratio R = ΔM_orb/M⁰_orb can exceed 50% with the introduction of ∼1% impurities. Unexpectedly, the ratio R is qualitatively insensitive to η, in high contrast to a naive expectation that R is proportional to the current suppression area πξ_J². The resulting giant impurity effect of M_orb originates from the nonlocal contribution of the itinerant circulation of electrons. The present study gives a natural explanation of why the cLC electronic states in kagome metals are sensitive to dilute impurities.

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