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Combination of random-barrier and random-trap models

K. Mussawisade·T. Wichmann·K. W. Kehr
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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.

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K. Mussawisade, T. Wichmann, K. W. Kehr. 1996-10-27. Combination of random-barrier and random-trap models. https://doi.org/10.1088/0953-8984%2F9%2F6%2F005

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