Itinerant ferromagnetism in the multiorbital Hubbard model: a dynamical mean-field study
Abstract
In order to resolve the long-standing issue of how the itinerant ferromagnetism is affected by the lattice structure and Hund's coupling, we have compared 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 {\it 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.
Cite
@article{arxiv.0706.3109,
title = {Itinerant ferromagnetism in the multiorbital Hubbard model: a dynamical mean-field study},
author = {Shiro Sakai and Ryotaro Arita and Hideo Aoki},
journal= {arXiv preprint arXiv:0706.3109},
year = {2009}
}