Influence of frozen non-magnetic impurities on phase transitions in two-dimensional Potts model

An influence of frozen nonmagnetic canonically distributed impurities on phase transitions in two-dimensional Potts model with the number of spin states q = 5 has been studied by Wolf cluster Monte Carlo algorithm. The systems with linear size L = 20–160 and with spin concentrations p = 1.0, 0.9 are considered. Using the fourth-order Binder cumulant method and the histogram data analysis method it is shown that introducing a weak frozen disorder into the system in the form of non-magnetic impurities (p = 0.9) changes the first-order phase transition to the second-order phase transition. (author)