Dresden 2011 – scientific programme

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O: Fachverband Oberflächenphysik

O 90: Electronic structure III

O 90.6: Talk

Thursday, March 17, 2011, 18:30–18:45, WIL C107

Modification of field emission resonances by Cu and Cu/Ag islands on Ag(100) — •Christopher Zaum and Karina Morgenstern — Institut für Festkörperphysik, Abteilung ATMOS, Gottfried Wilhelm Leibniz Universität, Appelstr. 2, D-30167 Hannover, Germany

We deposited Cu islands containing 10 to 500 atoms on a clean Ag(100) surface at room temperature and investigated their electronic structure by STS spectroscopy with a low temperature scanning tunneling microscope. Islands containing less than 50 atoms per islands are pure Cu islands, while islands at sizes above 80 atoms per island are Cu/Ag alloy islands. STS measurements reveal that these two island types have a different impact on the field emission resonances (FERs) of the Ag(100) surface. While the observed modifications for large islands are marginal, noticeable shifts of the FERs occur for small islands. These different results in STS spectroscopy are discussed with respect to the different work functions of pure and alloyed islands. Such STS measurements could therefore be used to determine the composition of surface alloys with high spatial resolution.