Dresden 2011 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 23: Scanning probe methods II

O 23.2: Vortrag

Montag, 14. März 2011, 17:30–17:45, WIL C307

A strange disturbance in the force — •Jay Weymouth, Thorsten Wutscher, Joachim Welker, Thomas Hofmann, and Franz Giessibl — Universität Regensburg, Regensburg, Germany.

Although atomic contrast with NC-AFM was first reported over fifteen years ago on Silicon [1], several interesting questions remain concerning simultaneous STM and NC-AFM. Arai and Tomitori previously showed that the force signal could be varied with applied bias voltage [2]. Sugimoto and coworkers have recently demonstrated that the distance at which one typically acquires STM data is approximately 4 Å further from the surface than the distance one acquires AFM data [3]. Both sets of experiments were made with a standard cantilever at amplitudes around 200 Å. We have performed similar experiments with smaller amplitudes (<5 Å). A smaller amplitude not only increases the signal to noise ratio, it also simplifies the physical interpretation of the observed frequency shift and makes the measurement more sensitive to short-range forces.

1. Giessibl, F.J., Science, 267, 68 (1995)

2. Arai, M. and Tomitori, M., Phys Rev Lett, 93, 256101 (2004)

3. Sugimoto, Y. et al, Phys Rev B, 81, 245322 (2010)