title: Soft hubbard gaps in disordered itinerant models with short-range interaction.
abstract: We study the Anderson-Hubbard model in the Hartree-Fock approximation and the exact diagonalization under the coexistence of short-range interaction and diagonal disorder. We show that there exist unconventional soft gaps, where the single-particle (SP) density of states (DOS) A follows a scaling in energy E as A(E) proportional, variantexp[-(-gammalog|E-E_{F}|);{d}] irrespective of electron filling and long-range order. Here, d is the spatial dimension, E_{F} the Fermi energy and gamma a nonuniversal constant. We propose a multivalley energy landscape as their origin. Possible experiments to verify the present theory are proposed.
authors.affiliation: Department of Applied Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Shinaoka
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Imada