Formation of edge dislocations in the surface constrained smectic a film

We study surface driven formation of a lattice of edge dislocations in the SmA phase in the semiinfinite geometry using Landau-Ginsburg phenomenologic al approach and estimate the conditions where the dislocation structure is stable over the tilted structure and the threshold for the formation of an edge dislocation on increasing the surface positional anchoring strength W- p. The detail structure of an edge dislocation is numerically studied as a function of W-p.