TRANSPORT IN IONIC CONDUCTING GLASSES

The frequency-dependent conductivity of glasses is explained in a treatment spanning the range of frequencies, 0 < omega < nu-ph almost-equal-to 10(12) Hz. A large spread of individual relaxation times is assumed. The connection between low frequency AC conduction and DC conduction is their common origin in non-local relaxation processes. This connection has already been exploited to derive results for sigma(omega) in the electronic systems known as the 'Fermi glass' and the 'electron glass', which are in quantitative agreement with experiment. In these systems, quantitative expressions are available for the distribution of relaxation times, in contrast to the situation in ionic conducting glasses. In ionic conducting glasses, as in the electron glass, the effects of Coulomb interactions in the sequential correlation of individual transitions is critical at low frequencies when the relaxation is non-local. The framework of the calculations is given by percolation theory.