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O: Fachverband Oberflächenphysik
O 93: Poster Session VII: Graphene and beyond I
O 93.11: Poster
Thursday, March 4, 2021, 10:30–12:30, P
Kinetic nanoscale friction and intermittent hybridization in graphene stacks on SiC — •Bartosz Szczefanowicz1, Leonhard Mayrhofer2, Andreas Klemenz2, Michael Moseler2, and Roland Bennewitz1 — 1INM - Leibniz Institute for New Materials, Saarbrücken, Germany — 2IWM Fraunhofer Institute for Mechanics of Materials, Freiburg, Germany
Graphene is an excellent lubricant on micro- and nanoscale due to its weak normal-to-plane interactions. Friction Force Microscopy (FFM) demonstrated ultralow friction for graphene on many different substrates. However, the friction force for epitaxial graphene on SiC(0001) increases dramatically above a normal load threshold [1]. We suggest that the observation can be explained by a pressure-induced temporal and local orbital rehybridization from sp2 to sp3 and a corresponding change of interlayer van der Waals interaction into metastable covalent bonds [2].
We report friction force measurements for graphene/SiC(0001) in ultrahigh vacuum as function of normal load and sliding rate and compare the results to atomistic simulations based on density functional theory (DFT). An excellent agreement of the load-dependence reveals friction mechanisms involving pressure-induced intermittent bonds.
[1] T. Filleter, R. Bennewitz, Physical Review B, 81 (2010), 155412
[2] Y. Gao, et al, Nature Nanotechnology, 13 (2018), 133-+.