Diffusion Coefficient of Particles in Lattices with Random-Barriers and wide Distribution of Transition Rates
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Date
1995-06
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Addis Ababa University
Abstract
We have investigated the mean-square displacements of particles that perform random
walks in two and three-dimensional lattices with random barriers with uniform
distributions of activation energies. The lattice we considered is a mathematical lattice.
For the same model Avramov, Milchev, and Argyrakis [phys.rev.E 47 2303 (1993)]
discussed the crossover between anomalous and normal diffusion, but they did not
Analyze the behavior of the mean-square dispalcements at long times where normal
diffusion occurs. We point out that the asymptotic diffusion coefficients are well
described by the effective- medium theory in the range of parameters investigated ; they
are in disagreement with the predictions of critical-path arguments in dimension d=3
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Keywords
Lattices with Random-Barriers