Griffiths phase and critical behavior of the two-dimensional Potts models with long-range correlated disorder

The q-state Potts model with long-range correlated disorder is studied by means of large-scale Monte Carlo simulations for q = 2, 4, 8, and 16. Evidence is given of the existence of a Griffiths phase, where the thermodynamic quantities display an algebraic finite-size scaling, in a finite range of temperatures. The critical exponents are shown to depend on both the temperature and the exponent of the algebraic decay of disorder correlations, but not on the number of states of the Potts model. The mechanism leading to the violation of hyperscaling relations is observed in the entire Griffiths phase.