Non-Fermi liquid effects in the low temperature behaviour of a disordered strongly interacting electron system

Abstract

We examine a version of the U=[infinity] Hubbard model for which a 1/N expansion can be carried out (N being the orbital degeneracy), in the presence of disorder. We calculate the 1/N corrections to the partition function and single particle decay rate, treating the disorder by summing up those ladder diagrams in the impurity potential that are known to yield the diffusion pole in conventional disorder theories. We find, away from the critical metal-insulator filling, agreement with earlier weak interaction theories with a single parameter characterising the effective interaction, while close to the critical filling we find novel power law corrections whose origin may be traced to the strong momentum dependence of the diffusion pole in the density correlation function.