Unbinding transition of the interface of a two-dimensional Ising-model system with a defect zone in the bulk.

Abstract

By introducing a defect zone instead of a single defect line in the bulk, a modified form of the AB model of Forgacs, Svrakic, and Privman is investigated. It is found that when the defect zone is far away from the substrate the first-order unbinding transition still exists at a temperature ${\mathit{T}}_{1}$ below the critical point of the two-dimensional Ising model, while when it is near the substrate no wetting transition can take place because the inhomogeneity constrains the formation of the wetting layer.