High-resolution photoemission study of hcp-Co(0001)

Using a monochromatized high-flux He discharge lamp, we have investigated the electronic bands of hexagonal-closed packed (hcp) Co(0001) near the Fermi energy at room temperature. Particularly, sections through the Fermi surface have been measured by high-resolution photoemission using photon energies of 21.2 eV and 40.8 eV. Compared to analogous measurements from copper and nickel surfaces, the features here are less sharp, even though LEED patterns indicate a similar degree of surface order. Still, an interpretation of these data in terms of calculated Fermi surface contours is possible. The Fermi wave vectors of the minority d-hole pocket centered at the Γ-point, are well reproduced. This is furthermore corroborated by polar-angle dependent dispersion measurements along two high-symmetry azimuths.