Critical behavior of the site-diluted three-state Potts model on the square lattice

Abstract

 The effects of quenched disorder on the critical behavior of the site-diluted three-state Potts model is investigated through Monte Carlo simulations. Finite-size scaling analysis is employed to extract the critical exponents γ and ν across a range of dilution concentrations from the pure system (d = 1.0) down to d = 0.70, remaining above the percolation threshold. The results reveal a systematic increase in the critical exponents with increasing disorder, suggesting a crossover from the pure three-state Potts universality class toward that of the two-dimensional Ising model, and at stronger dilution, toward percolation-like behavior. Notably, the ratio γ/ν remains approximately constant throughout, providing evidence for weak universality. The critical temperature determined from the Binder cumulant crossings is also found to decrease linearly with dilution, consistent with reduced connectivity in the system.