Ultraviolet-photoemission studies of niobium

The valence band of Nb has been studied with high-resolution ultraviolet photoemission for photon energies up to 12 eV. The measurements were performed under ultrahigh-vacuum conditions (${10}^{-11\mathrm{}}$ Torr) on electron-gun evaporated thin films. The experimental distribution curves are discussed in view of a theoretical band-structure calculation by Mattheiss. There is an over-all good agreement between theory and experiment both concerning $d$-band width and structure in the valence band. Niobium also shows interesting surface properties and is extremely sensitive to contamination.