Biased diffusion in anisotropic disordered systems

TLDR: This work investigates a diffusion process into an anisotropic disordered medium in the presence of a bias and observes a transition from pure to drift diffusion when the bias reaches a threshold B(c).

Abstract: 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 ,a neffective exponent is used to characterize the diffusion process. This Bc is also compared with another estimation for the critical field.