Dresden 2011 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 57: Nanotribology

O 57.1: Vortrag

Mittwoch, 16. März 2011, 16:30–16:45, WIL C307

Driven colloidal monolayers on periodic and quasiperiodic substrate potentials as model systems for nanotribology — •Thomas Bohlein, Jules Mikhael, and Clemens Bechinger — 2. Physikalisches Institut, Universität Stuttgart, Germany

Tribology - the science of interacting surfaces in relative motion - is of great importance for all technical applications where moving bodies are in contact. Experimental tools such as the friction force microscope enable the investigation of frictional processes at atomic scales. Here we present a study which allows to probe friction on the micrometer range. We experimentally study the sliding behavior of a two dimensional colloidal crystal interacting with periodic and quasiperiodic light induced substrate potentials created by overlapping several laser beams. Translations of the sample cell correspond to applying a lateral force on the crystal in any desired direction. The crystal's response is then studied in real space by digital video microscopy. We observe high friction for periodic commensurate systems, whereas for periodic incommensurate and quasiperiodic systems the static friction force almost vanishes, giving rise to superlubric sliding states. In a final step, we examine the effect of phononic and phasonic excitations of the quasiperiodic substrate potential on the sliding friction.