Wetting phenomena in bcc binary alloys

We study the influence of the surface orientation on the wetting behavior of bcc binary alloys, using a semi-infinite lattice model equivalent to a nearest-neighbor Ising antiferromagnet in an external field. The salient feature of the model is the generation of an ``effective'' ordering surface field for symmetry-breaking surface orientations like (100). Such a field couples to the local order parameter at the surface and leads to the occurrence of wetting phenomena below the critical temperature T_c. Utilizing a Ginzburg-Landau continuum model which has been derived earlier from the lattice mean-field theory, the wetting phase diagram is calculated.