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

The wetting transition in a two-dimensional Ising model with a free rough s urface at which a boundary magnetic field acts is studied using Monte Carlo simulations. In order to generate such rough surfaces we have used a simpl e one-dimensional solid-on-solid model. Apart from the basic thermodynamic quantities, such as susceptibilities, total average magnetizations, heat ca pacities, we have also recorded two magnetization distribution functions. T he final results have been obtained by averaging simulation data over sever al 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. (C) 2000 Elsevier Scie nce B.V. All rights reserved.