Evidence of itinerant 3d-electron character in the angle-resolved photoemission spectra of CoO

Evidence of itinerant (band-like) behaviour of the Co 3d states in paramagnetic CoO has been adduced from CoO(001) angle-resolved photo emission spectra. Two d bands are identified, which disperse 0.4 eV and 1.7 eV between Γ and X. In broad terms the results are consistent with a recently proposed model of the electronic structure in which the insulating gap arises largely from an exchange potential perturbation of the one-electron band structure.