Hopping transport in the presence of site-energy disorder: Temperature andconcentration scaling of conductivity spectra

Recent measurements on ion-conducting glasses have revealed that conductivi ty spectra for various temperatures T and ionic concentrations n can be sup erimposed onto a common master curve by an appropriate rescaling of the con ductivity and frequency. In order to understand the origin of the observed seating behavior, we investigate by Monte Carlo simulations the diffusion o f particles in a lattice with site energy disorder for a wide range of both T and n values. While the model can account for the changes in ionic activ ation energies upon changing n, it in general yields conductivity spectra t hat exhibit no scaling behavior. However, for typical n and sufficiently lo w T values, a fairly good data collapse is obtained analogous to that found in experiment.