Münster 1999 – wissenschaftliches Programm
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O: Oberflächenphysik
O 22: Nanostrukturen
O 22.5: Vortrag
Mittwoch, 24. März 1999, 15:30–15:45, S1
Theory of adsorbate manipulations in the STM — •D. Drakova1 and G. Doyen2 — 1University of Sofia, J. Bourchier 1, Sofia 1164, Bulgaria — 2LM-Universität München, Sophienstr. 11, D-80333 München, FRG
The interaction energies, forces, electron-hole excitation spectra, STM-images and ST-spectra on adsorbate covered metal surfaces are calculated within the same theory and a model consisting of two half infinite metal electrodes, separated by a vacuum region of nanscopic dimensions where adsorbed atoms, molecules and cluster of atoms forming the tip are embedded [1]. The theory yields a realiable description of the multiplicity of the adspecies, which is crucial for the STM-imaging. The surface of the interaction energy with the tunnel tip, consisting of an Al atom adsorbed on Al(111), and the tunneling current are calculated, taking into account the interactions with the multiple images in the two electrodes in addition to the interactions in the local region of nanoscopic dimensions. The conditions where the pushing and pulling mechanisms of CO on Pt(111) operate are elucidated and the possibilities for tip manipulation of single adsorbed oxygen atoms on Al(111) are discussed.
[1] E. Koetter, D. Drakova, G. Doyen, Phys. Rev. B 53, 16595 (1996).