CRITICAL WETTING IN THE SQUARE ISING-MODEL WITH A BOUNDARY FIELD

The Ising square lattice with nearest-neighbor exchange J>0 and a free surface at which a boundary magnetic field H1 acts has a second-order wetting transition. We study the surface excess magnetization and the susceptibility of L×M lattices by Monte Carlo simulation and probe the critical behavior of this wetting transition, applying finite-size scaling methods. For the cases studied, the results are not consistent with the presumably exactly known values of the critical exponents, because the asymptotic critical region has not yet been reached. Implication of our results for critical wetting in three dimensions and for the application of the present model to adsorbed wetting layers at surface steps are briefly discussed. © 1990 Plenum Publishing Corporation.