Regensburg 2004 – wissenschaftliches Programm

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O: Oberflächenphysik

O 11: Elektronische Struktur (Experiment und Theorie) I

O 11.5: Vortrag

Montag, 8. März 2004, 16:45–17:00, H44

Sub-Monolayer growth of Pb on Ag(111) — •Gero Wittich, Lucia Vitali, Peter Wahl, M. Alexander Schneider, Christian Ast, Lars Diekhöner und Klaus Kern — Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany

The growth of ultrathin Pb films deposited on Ag(111) surfaces is studied by low temperature scanning tunneling microscopy (STM). Pb is known to form surface alloys with e.g. Cu although it is immiscible with noble metals in the bulk. In the system Pb/Ag(111) we observe, that the Pb atoms are incorporated in the first Ag layer and repel each other. With increasing coverage a long range ordered (√3 x √3 )R30^∘ surface alloy forms. Above 0.3 monolayers, dealloying starts and hexagonal close packed Pb regions, showing a moiré pattern, coexist with the surface alloy phase.

We discuss the formation of these phases as well as the electronic properties of this system, investigated by means of scanning tunnelling spectroscopy (STS).