Photoemission and electronic structure of iron

Abstract

Photoemission studies of the valence-band structure of iron are carried out in the photon energy range 11.8 < or = h ..omega.. < or = 21.2 eV. A prominent peak at 0.58 +- 0.03 eV and a less pronounced maximum at 2.4 +- 0.2 eV below the observed Fermi level in the energy-distribution curve at h ..omega.. = 21.2 eV are shown to characterize the profile of the occupied states. Our results are compared with other experimental data and with band-structure calculations. Soft-x-ray appearance potential spectra, x-ray continuum isochromats, and the present ultraviolet-photoemission spectra, when taken together, suggest an upper limit of 1.9 eV for the exchange splitting of the spin-up and spin-down d bands. Finally, we have discussed the results of photoelectron spin-polarization measurements. Previous interpretations of these experiments indicated apparent contradiction with the Slater-Stoner-Wohlfarth itinerant-electron band theory of ferromagnetism.