Anisotropic surface model in two substrate dimensions

We introduce an anisotropic equilibrium surface model which has a restricted solid-on-solid condition in the y-direction and a restricted curvature condition in the x-direction. There are three different regimes: W(t) ∼ tβ1 for t < L2, W(t) ∼ tβ2 for L2 < t < L4 and W(L) ∼ Lα for t >> L4. The surface width in the y-direction shows that the roughness exponent αrsos is near 1/4, but the surface width for the x-direction indicates that the roughness exponent α is near 0.95. A possible continuum equation for the model is also discussed.