FINITE-SIZE EFFECTS FOR PHASE SEGREGATION IN A 2-DIMENSIONAL ASYMMETRIC EXCLUSION MODEL WITH 2 SPECIES

We investigate the stationary states of a two-dimensional lattice gas model with exclusion, in the presence of an external field. The lattic e is populated by equal numbers of positively and negatively charged p articles. An analytical mean-field approach and Monte Carlo simulation s give strong evidence of the fact that at any finite density the only relevant stationary state of the system in the thermodynamic limit is inhomogeneous, consisting of a strip of particles transverse to the f ield. In the inhomogeneous phase, the density profiles and the current measured by Monte Carlo simulations are closely related to those foun d in mean field. The same is true for the finite-size behavior of the system.