Two-electron excitations and the low temperature properties of glasses

Abstract

Abstract The Holstein molecular-ion model is used to examine in some detail the wave-function describing a two-electron excitation, or double polaron, proposed by Anderson (1975) as a model for a localized state in certain amorphous solids. This wave-function forms the basis of a calculation for the probability of a transition of the double polaron from one localized site to another. The calculation shows that at low temperatures the double polaron is essentially immobile, and contrary to Anderson's suggestion, cannot contribute to the heat capacity below 1 K.