材料期刊网

A particle diffusing in a disordered medium with a Gaussian distribution of potential well depths is studied. The transition rates are related to the random potentials in the well-known Arrhenius form. A log-normal distribution of transition rates is naturally established. Finally, we show that the behaviour of diffusing particles in the one-dimensional case can be expressed as ln 1/2 approximately (kT/sigma)2(ln t)2, when kT/sigma << 1 (low temperature), where sigma, T and k are the variance of the Gaussian distribution, the absolute temperature and the Boltzmann constant, respectively. When kT/sigma >> 1 (high temperature) the normal type of diffusion behavior is exhibited. The anomalous types of diffusion behavior associated with higher dimensions are also investigated.