Critical Wetting with Short-Range Forces: Is Mean-Field Theory Valid?

Critical and tricritical wetting transitions are studied in a simple-cubic nearest-neighbor Ising model. The magnetization $m_1$ in the surface layer and the susceptibilities ${\chi }_{11}=\frac{\partial m_1}{\partial H_1}$ and ${\chi }_1=\frac{\partial m_1}{\partial H}$, where $H_1$ is the surface field and $H$ the bulk field, are calculated by use of Monte Carlo methods. The critical behavior of these quantities is found to be consistent with simple mean-field behavior; the singularities predicted by various renormalization-group treatments are not observed.