Anisotropic thermally activated diffusion in percolation systems

BUSTINGORRY SEBASTIAN; INSUA GRISELDA L

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

American Physical Society

Lugar: New York; Año: 2003 vol. 68 p. 12101 - 12104

1063-651X

We present a study of static and frequency-dependent diffusion with anisotropic thermally activated transition rates in a two-dimensional bond percolation system. The approach accounts for temperature effects on diffusion coefficients in disordered anisotropic systems. Static diffusion shows an Arrhenius behavior for low temperatures with an activation energy given by the highest energy barrier of the system. From the frequency-dependent diffusion coefficients, we calculate a characteristic frequency vc~1/tc , related to the time tc needed to overcome a characteristic barrier. We find that vc follows an Arrhenius behavior with different activation energies in each direction.