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DS: Fachverband Dünne Schichten
DS 3: Metal Layers and Multilayers
DS 3.3: Talk
Monday, March 26, 2007, 10:00–10:15, H34
Evolution of the Quantum Well States in Ag layers on Au(111) — Frank Forster1, Eugen Gergert1, •Andreas Nuber1, Azzedine Bendounan1, Li Huang2,3, Xingao Gong2, and Zhenyu Zhang3 — 1Universität Würzburg, Experimentelle Physik II, Am Hubland, 97074 Würzburg — 2Surface Physics Laboratory and Department of Physics, Fudan University, Shanghai 200433, P.R. China — 3Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
Electronic quantum well states (QWS) confined in ultrathin films are of great scientific interest. Outside the substrate energy gap the confinement is supressed. They can couple with substrate states and form quantum well resonances (QWR). We present systematic studies on epitaxial layer-by-layer growing Ag films up to 45 ML on Au(111) using angular resolved photoelectron spectroscopy (ARUPS) (ΔE = 3 meV, ΔΘ = 0.3∘).
Our data in combination with density functional theory show the transition from QWR to QWS. We investigated the localization of the states in terms of their center-of-charge, peak position and lineshape. In contrast to comparable systems like Ag/W(110) QWS in Ag/Au(111) are formed not before a thickness of ≈ 8 ML. The center-of-charge and the peak position are localized within the Ag overlayer and Au energy gap, respectively, at the same film thickness and hence can be used as criteria for the formation of QWS. Further investigations on their lineshape close to the substrate gap edge allow access to further many-body characteristics of the QWS.