k-dependent exchange splitting of empty bands in nickel

Spin-polarized inverse photoemission spectroscopy has been used to study the spin-dependent unoccupied electronic structure of nickel. Measurements involved the study of Ni(110) in the Gamma Y azimuth. A k-dependent spin splitting with measured spectral values ranging from 113 +/- 20 meV to 337 +/- 51 meV has been resolved for a bulk sp-like band. These results are consistent with differential sp/d hybridization. Furthermore, an exchange splitting of 190 +/- 30 meV is detected for a Shockley surface state. The experimental observations are in good agreement with calculations employing one-step theory.