Experimental E(k→) dispersions for the Zn 3d states: Evidence for itinerant character

Abstract

Using angle-resolved photoemission from Zn (0001) we observe that the Zn 3d states exhibit energy-band dispersion (0.17 eV from Γ6+ to Γ5- for the upper d band) and k-dependent polarization selection rules. The d bands are centered at 10 eV below the Fermi energy EF and are 1.0 eV wide (Γ4- to Γ5-). In contrast, ab initio band calculations using a Hedin-Lundqvist potential yield d bands centered at ∼8.3 eV below EF that are 1.5 eV wide and disperse by 0.33 eV, thus indicating the significance of self-energy corrections for these deep-lying narrow bands. Upon empirically correcting the d-band position by adjusting the exchange parameter α in a nonrelativistic Xα calculation, the calculated bandwidth (1.0 eV) and dispersion are also in agreement with experiment. Experimental critical points are (energies relative to EF): Γ5-=-9.60 eV, Γ6+=-9.77 eV, Γ6-=-10.05 eV, - 10.30 eV, Γ5+=-10.05 eV, - 10.31 eV, Γ4-=-10.62 eV. The observed initial-state lifetime broadening (full width of half maximum) is 0.3 eV at the top of the d bands and 0.5 eV at the bottom of the d bands. © 1980 The American Physical Society.