title: Switching atomic friction by electrochemical oxidation.
abstract: Friction between the sliding tip of an atomic force microscope and a gold surface changes dramatically upon electrochemical oxidation of the gold surface. Atomic-scale variations of the lateral force reveal details of the friction mechanisms. Stick-slip motion with atomic periodicity on perfect Au(111) terraces exhibits extremely low friction and almost no dependence on load. Significant friction is observed only above a load threshold at which wear of the surface is initiated. In contrast, irregular stick-slip motion and a linear increase of friction with load are observed on electrochemically oxidized surfaces. The observations are discussed with reference to the amorphous structure of the oxo-hydroxide surface and atomic place exchange mechanisms upon oxidation. Reversible, fast switching between the two states of friction has been achieved in both perchloric and sulfuric acid solutions.
authors.affiliation: Department of Physics, McGill University , Montreal, Canada.
authors.forename: Aleksander
authors.initials: A
authors.lastname: Labuda
authors.forename: Florian
authors.initials: F
authors.lastname: Hausen
authors.forename: Nitya Nand
authors.initials: NN
authors.lastname: Gosvami
authors.forename: Peter H
authors.initials: PH
authors.lastname: Grütter
authors.forename: R Bruce
authors.initials: RB
authors.lastname: Lennox
authors.forename: Roland
authors.initials: R
authors.lastname: Bennewitz