Phase diagrams of multilayer films and the Potts lattice-gas model of adsorption

Abstract

The Potts lattice-gas model is examined via Monte Carlo simulations and a mean-field approximation to obtain phase diagrams for multilayer adsorbed films. The advantage of the model is that it has three bulk phases, interpreted here as solid, liquid, and gas, allowing one to study the relationships between the phase transitions of the film and the bulk triple point. For our choices of coupling parameters, we find a solid film that wets the substrate and that melts, forming a liquid film, below the bulk triple-point temperature and either above or below the bulk roughening temperature. The liquid film wets the substrate above the bulk triple point but not below.