Berlin 2008 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 55: Poster Session III - MA 141/144 (Methods: Atomic and Electronic Structure; Particles and Clusters; Heterogeneous Catalysis; Semiconductor Substrates: Epitaxy and Growth+Adsorption+Clean Surfaces+Solid-Liquid Interfaces; Oxides and Insulators: Solid-Liquid Interfaces+Epitaxy and Growth; Phase Transitions; Metal Substrates: Adsorption of Inorganic Molecules+Epitaxy and Growth; Surface Chemical Reactions; Bimetallic Nanosystems: Tuning Physical and Chemical Properties; Oxides and insulators: Adsorption; Organic, polymeric, biomolecular films; etc.)
O 55.4: Poster
Mittwoch, 27. Februar 2008, 18:30–19:30, Poster F
Atomically Resolved Kelvin Probe Force Microscopy Measurements Analysed by a nc-AFM simulator — •Thilo Glatzel1 and Laurent Nony2 — 1Department of Physics, University of Basel, Klingelbergstr. 82, 4056 Basel, Switzerland — 2L2MP, UMR CNRS 6137, Univ. d'Aix-Marseille III, 13397 Marseille Cedex 20, France
Amplitude-Modulation Kelvin probe force microscopy (AM-KPFM) experiments have shown frequently atomically resolved contact potential difference (CPD) images. In this work, we report numerical investigations performed with a modified scheme of our nc-AFM simulator [1], with the goal to address the origin of such a contrast.
For that purpose, the core of our simulator has been modified to mimic the AM-KPFM setup. In AM-KPFM, the bias voltage that is applied between the tip and the surface is modulated at a frequency that matches the one of the second eigenmode of the cantilever. The long-range, short-range and electrostatic forces used to describe the system are derived from analytical expressions. The coupling between the first and the second eigenmodes of the cantilever will also be discussed.
Our results reproduce the experimental observations, thus showing that atomic variations of the CPD that are observed experimentally very likely reveal the atomic variations of the electrostatic potential at the surface of the ionic crystal.
[1] L. Nony et al., Phys Rev B 74, 235439 (2006).