TEMPERATURE-DEPENDENCE OF MIDINFRARED PEAKS IN HIGH-T-C PEROVSKITES

The temperature dependence of midinfrared spectra sigma(omega,T), the Hall coefficient R(H)(T), and thermoelectric power S(T) have been calc ulated on the basis of a two-fluid model consisting of localized polar ons and delocalized carriers. It is shown that in the case of intermed iate polarons, the in-plane temperature dependence of sigma(omega) is determined by the thermal activation energy and can both increase and decrease with temperature in agreement with the observed results. The same charge carriers were used to calculate R(H)(T) and S(T). The temp erature dependence of the Hall coefficient and thermoelectric power is determined by the same thermal activation energy and the agreement wi th experiments is good.