2-DIMENSIONAL WETTING TRANSITION IN A CORRUGATED POTENTIAL

A simple model for the wetting or depinning transition of a two-dimens ional solid-on-solid (SOS) interface in a short-range periodic pinning potential which alternates between attraction and infinite repulsion is analysed exactly. The interface is specified by transverse displace ment variables xi which vary continuously in the interval x(min) < x(i ) < infinity, and the stretching energy is proportional to Sigma(i) \x (i+1)-x(i)\. Both the semi-infinite and infinite geometries x(min) = 0 , -infinity are considered. For the most part the wetting transition i n the continuum model is similar to the transition in restricted SOS m odels with corrugated potentials, in which the xi are restricted to in tegers and x(i+1) - x(i) to +/-1, 0, but there are some qualitative di fferences in the phase diagrams involving re-entrant behaviour.