Berlin 2024 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 51: Focus Session: Molecular Nanostructures on Surfaces: On-Surface Synthesis and Single-Molecule Manipulation II
O 51.10: Vortrag
Mittwoch, 20. März 2024, 17:30–17:45, HE 101
Friction over single chemical bonds — Oliver Gretz1, Lukas Hörmann2,3, •Shinjae Nam1, Oliver T. Hofmann2, Franz J. Giessibl1, and Alfred J. Weymouth1 — 1Universität Regensburg, Deutschland — 2TU Graz, Österreich — 3University of Warwick, UK
Friction is a phenomenon that acts on many different length scales. With a sharp nanometer-sized tip, lateral forces can be measured and phenomena like anisotropy or superlubricity can be observed [1, 2]. However, the *large* tip prevents measurements of single chemical bonds. But is this spatial resolution necessary to understand sliding friction? How much does the energy loss differ when sliding over different chemical bonds? We performed lateral force microscopy, in which the tip oscillates laterally above the surface, with small amplitudes and a CO-terminated tip to be directly sensitive to the dissipated energy above single chemical bonds [3]. By comparing the dissipation over different covalent bonds, we found that the local potential energy landscape plays an important role in sliding friction. We were also able to observe dissipation over single O**H bonds. Our findings show that a complete understanding of friction requires a description of the individual chemical bonds at the surface.
1.*Liley, M. et al., Science, 280(5361), 273-275, (1998). 2.*Dienwiebel, M. et al., Physical review letters, 92(12), 126101, (2004). 3.*Weymouth, A. J. et al., Physical Review Letters, 124(19), 196101, (2020).
Keywords: Lateral force microscopy; Atomic force microscopy; Friction; Energy dissipation