Dresden 2006 – wissenschaftliches Programm
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O: Oberflächenphysik
O 27: Scanning probe techniques II
O 27.11: Vortrag
Dienstag, 28. März 2006, 18:15–18:30, WIL B321
Relating structure and friction: Energy dissipation during the lateral manipulation of antimony nanoparticles — •Markus Heyde1, Claudia Ritter2, Klaus Rademann2, and Udo D. Schwarz3 — 1Fritz-Haber-Institute of the Max-Planck-Society, Faradayweg 4-6, D-14195 Berlin, Germany — 2Institute of Chemistry, Humboldt University Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany — 3Department of Mechanical Engineering, Yale University, P.O. Box 208284, New Haven, CT 06520-8284, USA
Despite its daily-life importance, the fundamentals of friction are still insufficiently understood. In particular, the interplay between friction, "true" contact area, and crystalline structure at the interface is an issue of current debate. Recently, a new technique had been introduced that allows determining the threshold energy dissipated during the lateral displacement of small nanoparticles on suitable substrates as a function of the particle-substrate contact area [1]. Here, we present results of an extensive study of antimony nanoparticles 1000 nm2 to 100000 nm2 in size moved in air on graphite substrates. Complementary studies by electron microscopy reveal the internal structure of the islands, showing a transition from amorphous to crystalline of the island’s cores at about 10000-15000 nm2 size, while the surface layers are composed of amorphous antimony oxide in all cases. However, despite the similarities of the amorphous surface layer, islands with crystalline core show significantly higher energy dissipation during motion than the ones with amorphous core. Possible reasons for this effect are discussed.
[1] Ritter et al., Phys. Rev. B 71, 085405 (2005).