Berlin 2015 – scientific programme
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O: Fachverband Oberflächenphysik
O 31: Tribology
O 31.7: Talk
Tuesday, March 17, 2015, 15:30–15:45, MA 144
Friction boosted by spontaneous epitaxial rotations — •Davide Mandelli1, Andrea Vanossi1,2, Nicola Manini1,2,3, and Erio Tosatti1,2,4 — 1SISSA, Trieste, Italy — 2CNR-IOM Democritos, Trieste, Italy — 3Universita degli Studi di Milano, Milano, Italy — 4ICTP, Trieste, Italy
It is well known in surface science that incommensurate adsorbed monolayers undergo a spontaneous, energy-lowering epitaxial rotation from aligned to misaligned relative to a periodic substrate. We show first of all that a model 2D colloidal monolayer in an optical lattice, of recent importance as a frictional model, also develops in full equilibrium a small rotation angle, easy to detect in the Moire pattern. The colloidal monolayer misalignment is then shown by extensive sliding simulations to increase the dynamic friction by a considerable factor over the aligned case. More generally, this example suggests that spontaneous rotations are rather ubiquitous and should not be ignored in all tribological phenomena between mismatched lattices.
This work was mainly supported by the ERC Advanced Grant 320796-MODPHYSFRICT, and partly by SINERGIA contract CRSII2 136287, by PRIN/COFIN contract 2010LLKJBX 004, by COST Action MP1303.