Hund’s Rule and Metallic Ferromagnetism

  title={Hund’s Rule and Metallic Ferromagnetism},
  author={J{\"u}rg Fr{\"o}hlich and Daniel Ueltschi},
  journal={Journal of Statistical Physics},
  • Jürg Fröhlich, Daniel Ueltschi
  • Published 2005
  • Mathematics, Physics
  • Journal of Statistical Physics
  • 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.