Substrate roughness-enhanced wetting in a two-dimensional Ising model with boundary fields

The wetting transition in a two-dimensional Ising model with a free rough surface at which a boundary magnetic field acts is studied using Monte Carlo simulations. In order to generate such rough surfaces we have used a simple one-dimensional solid-on-solid model. Apart from the basic thermodynamic quantities, such as susceptibilities, total average magnetizations, heat capacities, we have also recorded two magnetization distribution functions. The final results have been obtained by averaging simulation data over several replicas of the system of the same surface roughness. It has been shown that the wetting transition is located at a lower surface field than in the model with flat surfaces and that the critical value of the surface field decreases when the surface roughness becomes higher.