Phase transitions in adsorption-induced reconstruction model

In this work we analyze a simple model of adsorption-induced surface reconstruction, which is developed in the framework of the lattice gas model. The critical behavior of the substrate atoms is obtained by monitoring the specific heat and the fluctuations in the fraction of unreconstructed surfaces, where the critical temperature is calculated by using finite size scaling techniques. The phase diagram (critical temperature as a function of surface coverage) of the system is obtained for different conditions. Two different behaviors are obtained depending on the structures of the adsorbed gas. In fact, if the adsorption process favors the island formation, two critical regions appear, characterized by two critical temperatures, however, if the adsorbed particles do not form island there is only one critical region with one critical temperature. The mechanism of island formation is also discussed.