2004/04/30 by Juerg Froehlich, Daniel Ueltschi
Physics and Astronomy · Mathematics · #cond-mat.str-el #cond-mat.stat-mech #math-ph #math.MP
paper · pdf · doi:10.1007/s10955-004-2174-y
published as J. Statist. Phys. 118, 973-996 (2005) · 17 pages
arxiv created 2004/11/10 · arxiv updated 2009/12/01
We study tight-binding models of itinerant electrons in two different bands, with effective on-site interactions expressing Coulomb repulsion and Hund's rule. We prove that, for sufficiently large on-site exchange anisotropy, all ground states show metallic ferromagnetism: They exhibit a macroscopic magnetization, a macroscopic fraction of the electrons is spatially delocalized, and there is no energy gap for kinetic excitations.