title: Friction boosted by equilibrium misalignment of incommensurate two-dimensional colloid monolayers.
abstract: Colloidal two-dimensional monolayers sliding in an optical lattice are of recent importance as a frictional system. In the general case when the monolayer and optical lattices are incommensurate, we predict two important novelties, one in the static equilibrium structure, the other in the frictional behavior under sliding. Structurally, realistic simulations show that the colloid layer should possess in full equilibrium a small misalignment rotation angle relative to the optical lattice, an effect so far unnoticed but visible in some published experimental moiré patterns. Under sliding, this misalignment has the effect of boosting the colloid monolayer friction by a considerable factor over the hypothetical aligned case discussed so far. A frictional increase of similar origin must generally affect other incommensurate adsorbed monolayers and contacts, to be sought out case by case.
authors: International School for Advanced Studies (SISSA), Via Bonomea 265, 34136 Trieste, Italy.
authors: Davide
authors: D
authors: Mandelli
authors: International School for Advanced Studies (SISSA), Via Bonomea 265, 34136 Trieste, Italy.|CNR-IOM Democritos National Simulation Center, Via Bonomea 265, 34136 Trieste, Italy.
authors: Andrea
authors: A
authors: Vanossi
authors: International School for Advanced Studies (SISSA), Via Bonomea 265, 34136 Trieste, Italy.|CNR-IOM Democritos National Simulation Center, Via Bonomea 265, 34136 Trieste, Italy.|Dipartimento di Fisica, Università degli Studi di Milano, Via Celoria 16, 20133 Milano, Italy.
authors: Nicola
authors: N
authors: Manini
authors: International School for Advanced Studies (SISSA), Via Bonomea 265, 34136 Trieste, Italy.|CNR-IOM Democritos National Simulation Center, Via Bonomea 265, 34136 Trieste, Italy.|International Centre for Theoretical Physics (ICTP), Strada Costiera 11, 34151 Trieste, Italy.
authors: Erio
authors: E
authors: Tosatti