Berlin 2005 – wissenschaftliches Programm

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O: Oberflächenphysik

O 47: Rastersondentechniken III

O 47.4: Vortrag

Dienstag, 8. März 2005, 16:30–16:45, TU EB202

Quantitative investigation of tip-sample interaction on single-walled carbon nanotubes in the attractive force regimes — •Makoto Ashino, Timo Behnke, and Roland Wiesendanger — Institute of Applied Physics and Microstructure Research Center, University of Hamburg, Jungiusstrasse 11, D-20355 Hamburg

The three-dimensional force field spectroscopy measurement combined with atomic-resolution dynamic force microscopy imaging has allowed us to evaluate interaction forces acting between a foremost atom of the silicon-cantilever tip and specific atomic sites of a single-walled carbon nanotubes (SWNT) [1]. Quantitative analysis using a simple Lennard-Jones (L-J) potential leads to the finding that the short-range interatomic van der Waals forces are responsible for the atomic-scale contrast. The analysis also shows that the interaction forces deviate from the L-J fits at closer tip-sample distances than that showing the maximum attractive forces. The degree of deviation is site dependent as well. Using some model calculations, we try to analyze tip-sample interactions at closer distances. By taking softness and tip-induced relaxations of SWNTs into account, we discuss the dynamic response of the SWNT to variation of the tip-sample distance.

[1] M. Ashino et al., Phys. Phys. Lett. 93, 136101 (2004).