Dresden 2017 – scientific programme

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O: Fachverband Oberflächenphysik

O 58: Surface Science: Misc.

O 58.2: Poster

Tuesday, March 21, 2017, 18:30–20:30, P2-EG

Electrostatic, phononic and van der Waals friction on layered materials — •Dilek Yildiz, Marcin Kisiel, and Ernst Meyer — Universität Basel, Basel, Switzerland

An unintuitive friction is caused due relative motion of bodies with a few nanometres gap in-between. This non-contact friction phenomenon still awaits to be understood completely. Effects of such non-contact friction can be measured by oscillating a highly sensitive cantilever like a tiny pendulum over a surface. We studied with TaS2 and HOPG crystal surfaces, which are well known layered structures. Energy dissipation spectra measured on both materials have shown clear differences. While electrostatic interaction causes energy dissipation on TaS2 at low temperatures, van der Waals friction is observed on the same sample at high temperatures due to the phase transition. Rather, we observed the lack of electrostatic friction on HOPG and we measured phononic type of friction, which is due to the short range forces. Mechanism of energy dissipation on TaS2 depends on a temperature driven phase transition of the crystal. In this presentation we will discuss three different mechanisms of non-contact friction: Friction due to electrostatic, van der Waals and phononic interactions between tip and the sample.