Evidence for the itinerant electron model of ferromagnetism and for surface photoemission from angle-resolved photoemission studies of iron

Angle-resolved HeI photoemission spectra of Fe(001) are reported and interpreted within the framework of a direct transition model using Callaway's ferromagnetic band structure. The generally good agreement between predicted and experimental peak positions is taken to be strong support for the itinerant electron theory of ferromagnetism. Spectra taken with nearly grazing incidence p-polarized light, however, are not interpretable in terms of the direct transition model. The importance of electron refraction is noted, as is the value of interpolation calculations for interpreting ARP spectra.