Low-Mobility Electrons in Solids

摘要

For the narrow-band limit, when temperature broadening of the polaron energy levels is greater than the width of the conduction band (i.e., absorption-emission of a phonon is more probable than ordinary tunnelling), a model for the mobility of the (jumping) small polaron has been evaluated. The temperature dependence of the transition matrix elements suggested by Frohlich, Machlup, and Mitra is approximately that of the orthogonality integral for nearest-neighbor localized states. For a sufficiently small polaron, this has a maximum at a temperature governed by the ratio of the polaron size to the lattice spacing. For a charged Bose gas, the ground state energy and depletion parameter are calculated by Green function techniques, expanding in powers of the interparticle spacing other than the (usual) multiples of the three-fourth. (Author)