The Influence of Structure on the Itinerant Band Structure of Thin Metal Overlayers

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The electronic band structure of thin film overlayers can be altered by changing the crystal structure and lattice parameters. The correlation between crystal and band structures will be investigated by combining the powerful surface science techniques of angle-resolved photoemission and low energy electron diffraction (LEED). Overlayers will be forced into unusual crystal geometries and lattice spacings by epitaxially growing the overlayer on carefully chosen crystal substrates. The investigation will concentrate on selected overlayer materials chosen from the IIa and IIb elements and the noble gases. The band structure of the overlayers can be investigated by using photoemission to determine the binding energies of the valence bands as a function of the position in the Brillouin zone. This traditional technique of determining band structure will be complemented by a new method that consists in analyzing the relative photo-ionization partial cross-section of valence orbitals as a function of photon energy. LEED will be used to investigate the overlayer crystal lattice structure by comparing LEED intensity versus electron accelerating voltages with dynamical LEED calculations. By combining the two techniques of photoemission and atom beam scattering in the investigation of thin (0-10) monolayer films, insight into the importance of atomic orbital overlap and many electron effects upon electronic band structure will be provided.