Softening of first-order transition in three-dimensions by quenched disorder.
We study by extensive Monte Carlo simulations the effect of random bond dilution on the phase transition of the three-dimensional four-state Potts model that is known to exhibit a strong first-order transition in the pure case. The phase diagram in the dilution-temperature plane is determined from the peaks of the susceptibility for sufficiently large system sizes. In the strongly disordered regime, numerical evidence for softening to a second-order transition induced by randomness is given. Here a large-scale finite-size scaling analysis, made difficult due to strong crossover effects presumably caused by the percolation fixed point, is performed.
Chatelain
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C
Laboratoire de Physique des Matériaux, Université Henri Poincaré, Nancy 1, Boîte Postal 239, F-54506 Vandoeuvre les Nancy Cedex, France.
Berche
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B
Janke
W
W
Berche
P E
PE