A study of electronic structures of Pt3M (M=Ti,V,Cr,Fe,Co,Ni) polycrystalline alloys with valence-band photoemission spectroscopy -: art. no. 204717

The surface valence-band densities of states (DOS) of Pt3M (M=Ti,V,Cr,Fe,Co,Ni) polycrystalline alloys were investigated with ultraviolet photoemission spectroscopy. Upon annealing the ion-sputter-cleaned alloys at high temperatures, the observed valence-band DOS spectra clearly show the modified electronic structures on the surfaces suggesting the surface segregation of Pt as predicted in thermodynamic models. The measured d-band centers and widths for the annealed alloy surfaces show qualitatively the same trend as predicted by density-functional-theory calculations based on the model of a Pt skin on the topmost surface layer and a subsurface layer enriched in the 3d transition metal. (c) 2005 American Institute of Physics.