Cooperative Phenomena in Solid Electrolytes

A theory of cooperative effects in ionic solids is presented, which points to the ionic carrier density as the main source of the anomalous behavior found in solid electrolytes. Depending on the parameter values, it predicts either an exponential increase of the conductivity with temperature, or a discontinuous change of the conductivity with an associated peak in the excess specific heat. The predicted behavior corresponds to that found in most solid electrolytes, particularly Rb${\mathrm{Ag}}_4$ ${\mathrm{I}}_5$.