Oil-Water Interface in the Widom Model: Is It Smooth, Rough or Crumpled?

(Received 23 November 1994, revised 18 January 1995, accepted 6 February 1995)

Abstract
The interface in the two-dimensional Ising model with only nearest-neighbour ferromagnetic interactions is known to be rough at all temperatures T>0. The Widom model for ternary microemulsions is, effectively, a spin-1/2 Ising model with, not only nearest-neighbour ferromagnetic interactions, but also specific farther-neighbour antiferromagnetic interactions. We investigate the effects of these farther-neighbour interactions in the Widom model on the roughening properties of the interface by carrying out Monte Carlo simulations.