Temperature and wave-vector dependence of the spin-split band structure of Ni(111) along the Γ-Lline

Spin- and angle-resolved photoemission measurements on a Ni(111) single crystal along the {Γ}-L line exhibit a strong wave-vector dependence of the spin-resolved photoemission intensities upon increasing the temperature: For excitation with h{ν}=11.83 eV [i.e., at k{}2/3d({Γ}-L)] one observes a clear merging of the spin-split peaks with increasing temperature. The spin splitting at k{}1/2d({Γ}-L) (h{ν}=16.85 eV) is, however, independent of temperature. Upon approaching the Curie temperature, one observes the appearance of extra intensities at the binding energy of the respective opposite spin direction. Indications of an essentially temperature-independent spin splitting are also found at k{}1/3d({Γ}-L)(h{ν}=21.2 eV).