Randomness-induced evolution of first-order to second-order phase transition in the three-state Potts antiferromagnetic model on a triangular lattice

The three-state Potts antiferromagnetic model on the two-dimensional triangular lattice has a weak first-order transition in the pure case. Our Monte Carlo simulation displays a transition temperature at T=0.628, which is consistent with previous studies. The nature of phase transition due to the randomness of quenched bonds is considered in this study. The energy histogram shows a single Gaussian peak due to randomness of the bond, while the first-order phase transition displays distinct double peaks due to the coexistence of two states. The histogram analysis ascertains the significance of order variation from the first-order to the second-order phase transition in this system.