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 triang ular 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 c onsistent with previous studies. The nature of phase transition due to the randomness of quenched bonds is considered in this study, The energy histog ram arn shows a single Gaussian peak due to randomness of the bond, while t he first-order phase transition displays distinct double peaks due to the c oexistence of two states. The histogram analysis ascertains the significanc e of order variation from the first-order to the second-order phase transit ion in this system. (C) 2000 Published by Elsevier Science B.V. All rights reserved.