Effect of the Band States Near the Fermi Surface on the Magnetic Properties of Anderson's Extra-Orbital Model

Abstract

The magnetic properties of Anderson's ``extra‐orbital'' model are investigated. An exact ground‐state solution is obtained for the simple case in which the conduction band is replaced by a single effective band state. Using this solution, a criterion for a magnetic ground state is determined. The possible existence of a magnetic ground state is found to be critically dependent upon whether the energy level of the effective band state is on the Fermi surface or not. To study this critical behavior associated with band states near the FS, the full Anderson (continuum) model is investigated. It is shown that the ``extra‐orbital'' spin—flip scattering processes associated with band states near the FS produce a lnk T/Γ damping which prohibits the occurrence of a Hartree—Fock magnetic ground state.