Field-induced vacancy localization in a driven lattice gas: Scaling of steady states

With the help of Monte Carlo simulations and a mean-field theory, we invest igate the ordered steady-state structures resulting from the motion of a si ngle vacancy on a periodic lattice which is filled with two species of oppo sitely "charged" particles. An external field biases particle-vacancy excha nges according to the particle's charge, subject to an excluded volume cons traint. The steady state exhibits charge segregation, and the vacancy is lo calized at one of the two characteristic interfaces. Charge and hole densit y profiles, an appropriate order parameter, and the interfacial regions the mselves exhibit characteristic scaling properties with system size and fiel d strength. The lattice spacing is found to play a significant role within the mean-field theory.