Effect of electron-electron interactions on hopping and on delocalization

Abstract

In impurity bands the Coulomb interaction energies are of the same order as the disorder energy, and must therefore be considered. The effect of these interactions on the density of one-electron excitations (the Coulomb gap) is discussed. The Coulomb gap can be alleviated by many-electron hops. The role of such many-electron hops on hopping transport at very low temperatures is evaluated, and a tentative formula for the conductivity obtained. Relevant experimental work from the literature is discussed in the context of the many-electron effects. Finally, a brief discussion of the effects of interactions on the Anderson transition is presented.