Dynamic behavior of the interface of striplike structures in driven lattice gases

SARACCO, G. P.; ALBANO, E. V.

PHYSICAL REVIEW E - STATISTICAL PHYSICS, PLASMAS, FLUIDS AND RELATED INTERDISCIPLINARY TOPICS

American Physical Society

Año: 2008 vol. 78 p. 31132 - 31132

1063-651X

In this work, the dynamic behavior of the interfaces in both the standard and random driven lattice gas models (DLG and RDLG, respectively) is investigated via numerical Monte Carlo simulations in two dimensions. These models consider a lattice gas of density =1/2 with nearest-neighbor attractive interactions between particles under the influence of an external driven field applied along one fixed direction in the case of the DLG model, and a randomly varying direction in the case of the RDLG model. The systems are also in contact with a reservoir at temperature T. Those systems undergo a second-order nonequilibrium phase transition between an ordered state characterized by high-density strips crossing the sample along the driving field, and a quasilattice gas disordered state. For TTc, the average interface width of the strips (W) was measured as a function of the lattice size and the anisotropic shape factor. It was found that the saturation value W only depends on the lattice size parallel to the external field axis Ly and exhibits two distinct regimes: Wln  Ly for low temperatures, that crosses over to WL near the critical zone, I=1/2 being the roughness exponent of the interface. By using the relationship I=1/(1+I), the anisotropic exponent for the interface of the DLG model was estimated, giving I1, in agreement with the computed value for anisotropic bulk exponent B in a recently proposed theoretical approach. At the crossover region between both regimes, we observed indications of bulk criticality. The time evolution of W at Tc was also monitored and shows two growing stages: first one observes that Wln  t for several decades, and in the following times one has WtI, where I is the dynamic exponent of the interface width. By using this value we estimated the dynamic critical exponent of the correlation length in the perpendicular direction to the external field, giving z4, which is consistent with the dynamic exponent of the bulk critical transition z in both theoretical approaches developed for the standard model. A similar scenario was also observed in the RDLG model, suggesting that both models may belong to the same universality class.