The mobility anisotropy in tetragonal BaTiO3 in small polaron model

Abstract

Splitting of the mobility tensor component at the transition of BaTiO3 crystal from the cubic state to the tetragonal state is explained within the limits of the small-radius polaron model by the change of the overlapping integral magnitude. A quantitative comparison is made between theory and experiment and for this purpose the data obtained by Berglund and Baer, and Murakami were reproduced. From the same point of view Wemple's data about the dependence of mobility on hydrostatic pressure and a great difference of mobilities in SrTiO3 are considered.