Electronic structures of nanostructured transition metals on the Au (788) surface

The electronic structures of nanostructured transition metals (Fe, Co, Ni) grown by step decoration of the Au(788) surface are investigated by normal emission angle-resolved photoemission spectroscopy (ARPES). As the coverage of the transition metals is increased, the intensity of Au 5d valence bands decreases but the peak positions do not change, suggesting that the mixing between Au 5d and 3d of transition metals is negligibly weak. The coverage dependences of ARPES spectra near the Fermi level (E_F) for Fe, Co and Ni are discussed and compared with the photoemission results on bulk materials. In the higher coverage regions, we identify the observed 3d peaks near E_F as ferromagnetic exchange splitting bands with similar exchange energy to the bulk. In contrast, at lower coverages, the exchange splitting vanishes for Fe and Co and becomes small for Ni. The origins of this behaviour are attributed to atomic volume, structural dimensionality and finite temperature effects.