ISSN:
0142-2421
Keywords:
atomic force microscopy/lateral force microscopy (AFM/LFM)
;
atomic resolution
;
highly oriented pyrolytic graphite (HOPG)
;
computer simulation
;
stick-slip processes
;
atomic scale friction
;
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Physics
Notes:
Although the atoms in cleavage planes of graphite are arranged in a honeycomb structure, it is well known from experimental work that atomic force microscopy (AFM) yields a hexagonal structure, a phenomenon that has not been understood so far. Here, computer simulations of the atomic-scale imaging process on graphite by AFM are reported, showing that this behaviour can be explained within a simple model of elastic tip-sample interaction. Both the topographic (AFM) images and the friction force or lateral force microscopy (LFM) images were simulated as a function of the scanning direction relative to the graphite lattice and as a function of the cantilever force constant. The scan distortions and the skipped area due to the AFM/LFM imaging process were evaluated. Simulations were performed both in the presence and in the absence of atomic-scale stick-slip processes. It is shown that neither stick-slip processes nor an inequivalence of the A- and B-sites of graphite is necessary to generate a hexagonal AFM image when scanning an atomic honeycomb structure. Rather, the simulations demonstrate that due to the two-dimensional elastic lateral displacement of the cantilever, the potential maxima - which correspond to the positions of the honeycomb lattice - are avoided by the scanning path of the tip apex, resulting in a hexagonal structure of the AFM and LFM images.© 1997 John Wiley & Sons, Ltd.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
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