ELECTRONIC-STRUCTURE OF SILVER OVERLAYERS ON W(100)

The electronic structure of silver adsorbed on the (100) facet of a tu ngsten field emitter in the range of coverage from zero to three monol ayers has been studied experimentally by means of field and photofield emission spectroscopy. An analysis of work function and total emissio n current data yields evidence that adsorbed silver reduces the surfac e density of states at the Fermi energy It is found that adsorbed silv er both suppresses the Swanson hump in the surface density of states o f clean W(100) and also induces additional structures that depend larg ely on the number of complete overlayers. The experimental observation s are interpreted by means of self-consistent fully relativistic super cell calculations of the layer densities of electronic states at the t ungsten-vacuum and at the tungsten-silver-vacuum interface. The calcul ations predict silver-induced features in the surface density of state s that are generally consistent with the experimental observations.