Microcanonical Monte Carlo simulations of the first-order transition in the two-dimensional Potts model

Microcanonical Monte Carlo simulations have been implemented in the two-dimensional (2D) q -state Potts model. The ergodicity of this simulation technique for the Potts model is studied. It does not seem to depend on the value of q . A lack of ergodicity for small values of the system energy is reported and discussed. It has been found that the temperature dependences of physical quantities exhibit an `S'-shaped nature at the first-order transition. The degree of `S'-shaped nature was enhanced by increasing q and reducing the system size. We believe on the basis of our computer simulations that the `S' shape represents the equilibrium behaviour of a finite isolated system.