Dresden 2003 – wissenschaftliches Programm
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O: Oberflächenphysik
O 24: Postersitzung (Epitaxie und Wachstum, Oxide und Isolatoren, Elektronische Struktur, Oberfl
ächenreaktionen, Adsorption an Oberfl
ächen, Organische Dünnschichten)
O 24.33: Poster
Mittwoch, 26. März 2003, 14:30–17:30, P1
Temperature dependence of STM-thermovoltage measurements — •Bastian Weyers, Winfried Langenkamp, and Rolf Möller — Universität Essen, Fachbereich Physik, Institut für experimentelle Physik, 45117 Essen
The thermovoltage which arises if the tunneling tip and the sample are at different temperatures has been studied for the Au(111) surface. As shown previously this voltage provides a very sensitive analytical tool probing electronic states at the Fermi level with excellent lateral resolution. The electronic surface state of the Au(111) gives raise to standing waves in the thermovoltage due to scattering at step edges, adsorbates or the kinks of the 22 × √3 reconstruction.
We performed thermovoltage-STM-measurements on the Au(111) surface analyzing the dependence of the thermovoltage on the applied temperature difference. The signals by standing waves and by the flat surface have been studied separately. The results are compared to the theoretical work of Støvneng and Lipavský (PRB 42, 9214 (1990)), predicting that the thermovoltage should be proportional to Ttip2 − Tsample2.