Understanding the atomic-scale contrast in Kelvin Probe Force MicroscopyReport as inadecuate

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1 IM2NP - Institut des Matériaux, de Microélectronique et des Nanosciences de Provence 2 Department of Physics

Abstract : A numerical analysis of the origin of the atomic-scale contrast in Kelvin probe force microscopy KPFM is presented. Atomistic simulations of the tip-sample interaction force field have been combined with a non-contact Atomic Force Microscope-KPFM simulator. The implementation mimics recent experimental results on the 001 surface of a bulk alkali halide crystal for which simultaneous atomic-scale topographical and Contact Potential Difference CPD contrasts were reported. The local CPD does reflect the periodicity of the ionic crystal, but not the magnitude of its Madelung surface potential. The imaging mechanism relies on the induced polarization of the ions at the tip-surface interface owing to the modulation of the applied bias voltage. Our findings are in excellent agreement with previous theoretical expectations and experimental observations.

Keywords : Kelvin Probe Force Microscopy Local Contact Potential Difference Short-range Electrostatic Force Madelung Surface Potential Ionic crystal atomistic simulations on-contact Atomic Force Microscopy

Author: Laurent Nony - Adam Foster - Franck Bocquet - Christian Loppacher -

Source: https://hal.archives-ouvertes.fr/


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