Hamburg 2001 – wissenschaftliches Programm
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O: Oberflächenphysik
O 4: Elektronische Struktur (I)
O 4.4: Vortrag
Montag, 26. März 2001, 12:00–12:15, C
Quantum-well states in Ag(111)/Au(111) and Au(111)/Ag(111) double-layered on W(110) — •D. V. Vyalikh1,2, A. M. Shikin2, C. Schüßler-Langeheine1, A. Yu. Grigoriev1,2, H. Ott1, V. K. Adamchuk2, G. Kaindl1, and E. Weschke1 — 1Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany — 2Institute of Physics, St. Petersburg State University, Uljanovskaja 1, 198904 St. Petersburg, Russia
Quantum well states (QWS’s) in thin Ag(111)/Au(111) and Au(111)/Ag(111) overlayers grown epitaxially on W(110) were investigated by angle-resolved photoemission (PE). In the case of Ag films on top of Au(111)/W(110), pronounced QWS’s were observed over an extended energy range of almost 3 eV, much wider than for Ag films on bulk Au(111). This is explained by the formation of sp-like quantum well resonances (QWR’s) in the thin Au films; consequently, the Ag QWS’s exhibit avoided-crossing behavior at appropriate Au-film thicknesses. It was shown that the total thickness of the Au/Ag overlayer determines the positions of the QWS’s at binding energies larger than the band edge of Au at the L point of Brillouin zone. A simple quantum-well model can be applied, resulting in a quantitative description of the avoid-crossing behavior.