Electron States in Ferromagnetic Iron. I. Band Properties

A new band-structure calculation is reported for the ferromagnetic state of iron, in which the exchange interaction is given particularly careful treatment. A variational procedure was used with the wave functions expanded in terms of tight-binding functions and orthogonalized plane waves. Hybridization and spin polarization of the wave functions were allowed. Correlation corrections were incorporated. The energy bands are somewhat wider than those previously published; comparison is made with photoemission and optical reflection and x-ray emission data. The calculation leads self-consistently to the observed magnetic moment. The roles of intra-atomic exchange and itinerancy in the origin of iron's ferromagnetism are discussed.