Berlin 2015 – wissenschaftliches Programm
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MI: Fachverband Mikrosonden
MI 10: Poster: Microanalysis and Microscopy
MI 10.2: Poster
Mittwoch, 18. März 2015, 15:00–17:30, Poster B
Investigating Atomic Contrast in Atomic Force Microscopy and Kelvin Probe Force Microscopy on Ionic Systems using Functionalized Tips — •Leo Gross1, Bruno Schuler1, Fabian Mohn1, Nikolaj Moll1, Niko Pavliček1, Wolfram Stuerer1, Ivan Scivetti2, Konstantinos Kotsis2, Mats Persson2, and Gerhard Meyer1 — 1IBM Research – Zurich, 8803 Rüschlikon, Switzerland — 2University of Liverpool, Liverpool, L69 3BX, United Kingdom
We used chlorine vacancies in NaCl bilayers on Cu(111) as a model system to investigate atomic contrast as a function of applied voltage, tip height, and tip functionalization. The local contact potential difference (LCPD) acquired with Kelvin probe force microscopy showed the same qualitative contrast for all tip terminations investigated, which resembled the contrast of the electrostatic field of the sample. We find that the frequency-shift contrast, typically measured by non-contact atomic force microscopy, stems mainly from electrostatic interactions but its tip dependence cannot be explained by the tip dipole alone. With the aid of a simple electrostatic model and by density functional theory we investigate the underlying contrast mechanisms. [1]
[1] L. Gross et al. Phys Rev. B 90, 155455 (2014)