Dynamic behavior of the interface of strip-like structures in driven diffusive systems

Saracco, Gustavo P.; Albano, Ezequiel V.

Dynamic behavior of the interface of strip-like structures in driven diffusive systems

Authors

Description

The dynamic behavior of the interfaces in the standard and random driven lattice gas models (DLG and RDLG respectively) is investigated via numerical Monte Carlo simulations in two dimensions. For $T\lesssim T_c$, 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 $W^{2}_{sat}$ only depends on the lattice size parallel to the external field axis $L_y$ and exhibits two distinct regimes: $W^{2}_{sat}\propto \ln$ $L_y$ for low temperatures, that crosses over to $W^{2}_{sat}\propto L_y^{2α_I}$ near the critical zone, $α_I=1/2$ being the roughness exponent of the interface. By using the relationship $α_I=1/(1+Δ_I)$, the anisotropic exponent for the interface of the DLG model was estimated, giving $Δ_I\simeq 1$, in agreement with the computed value for anisotropic bulk exponent $Δ_B$ with a recently proposed theoretical approach. At the crossover region between both regimes, we observed indications of bulk criticality. The time evolution of $W$ at $T_c$ was also monitored and shows two growing stages: first one observes that $W \propto \ln$ $t$ for several decades, and in the following times one has $W\propto t^{β_I}$, where $β_{I}$ 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 $z_{\perp}^I\approx 4$, which is consistent with the dynamic exponent of the bulk critical transition $z_{\perp}^B$ 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.
12 pages, 17 figures