title: Itinerant ferromagnetism in the multiorbital Hubbard model: a dynamical mean-field study.
abstract: In order to resolve the long-standing issue of how itinerant ferromagnetism is affected by lattice structure and Hund's coupling, we compare various three-dimensional lattice structures in the single- and multiorbital Hubbard models with the dynamical mean-field theory with an improved quantum Monte Carlo algorithm that preserves the spin-SU(2) symmetry. The result indicates that both the lattice structure and the d-orbital degeneracy are essential for the ferromagnetism in the parameter region representing a transition metal. Specifically, (a) Hund's coupling, despite the common belief, is important, which is here identified to come from particle-hole scatterings, and (b) the ferromagnetism is a correlation effect (outside the Stoner picture) as indicated from the band-filling dependence.
authors.affiliation: Department of Physics, University of Tokyo, Hongo, Tokyo 113-0033, Japan.
authors.forename: Shiro
authors.initials: S
authors.lastname: Sakai
authors.forename: Ryotaro
authors.initials: R
authors.lastname: Arita
authors.forename: Hideo
authors.initials: H
authors.lastname: Aoki