Biased diffusion in anisotropic disordered systems

BUSTINGORRY SEBASTIAN; REYES EDUARDO R; CÁCERES MANUEL O

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

American Physical Society

Lugar: New York; Año: 2000 vol. 62 p. 7664 - 7669

1063-651X

We investigate a diffusion process into an anisotropic disordered medium in the presence of a bias. The medium is modeled by a two-dimensional square lattice in which the anisotropic disorder is represented by a bond percolation model with different occupation probabilities on each direction. The biased diffusion process is mapped by a random walk with unequal transition probabilities along and against the field (in the [1,1] direction) by performing Monte Carlo simulations. We observe a transition from pure to drift diffusion when the bias reaches a threshold Bc . In order to estimate this Bc , an effective exponent is used to characterize the diffusion process. This Bc is also compared with another estimation for the critical field.