Combination of random-barrier and random-trap models
Abstract
The temperature dependence of the diffusion coefficient of particles is studied on lattices with disorder. A model is investigated with both trap and barrier disorder that was introduced before by Limoge and Bocquet (1990 Phys. Rev. Lett. (65) 60) to explain an Arrhenian temperature-dependence of the diffusion coefficient in amorphous substances. We have used a generalized effective-medium approximation (EMA) by introducing weighted transition rates as inferred from an exact expression for the diffusion coefficient in one-dimensional disordered chains. Monte Carlo simulations were made to check the validity of the approximations. Approximate Arrhenian behavior can be achieved in finite temperature intervals in three- and higher-dimensional lattices by adjusting the relative strengths of the barrier and trap disorder. Exact Arrhenian behavior of the diffusion coefficient can only be obtained in infinite dimensions.
Cite
@article{arxiv.cond-mat/9610191,
title = {Combination of random-barrier and random-trap models},
author = {K. Mussawisade and T. Wichmann and K. W. Kehr},
journal= {arXiv preprint arXiv:cond-mat/9610191},
year = {2009}
}
Comments
18 pages LaTex, 3 embedded encapsulated Postscript figures, to be published in: J. of Phys.: Condensed Matter