Optical effects of small polarons at high frequencies with an application to reduced strontiumtitanate
AbstractTheoretical expressions for the complex electrical conductivity of small polarons are given for frequencies where
$$\bar \omega $$
 is an average frequency of the optical phonons. In this frequency range the complex conductivity is independent of the temperature. As an application an analysis is carried out of optical and d.c. data for reduced SrTiO3. It is shown that a consistent interpretation of these data as well with respect to their absolute magnitude as well with respect to their frequency dependence is possible in terms of the small polaron picture.