Lattice-gas models of dispersive transport in disordered materials

Dispersive transport is discussed on the basis of Monte-Carlo simulations of Coulombic-lattice-gas models involving different types of structural disorder. Particular attention is given to fractional power-laws in the time- and frequency-dependent response, a characteristic feature of many complex materials. The special case of diffusion in the presence of randomly placed Coulombic traps leads to conductivity spectra in very good agreement with experiments on ion-conducting glasses.