| In a pioneer experiment, Bechinger's group in Stuttgart realized the controlled sliding of two-dimensional colloidal crystals over laser-generated periodic or quasi-periodic potentials.[1] I will describe realistic simulations and arguments which besides reproducing the main experimentally observed features, demonstrate the potential impact of colloid sliding in crystal nanotribology.[2] The free motion of solitons and antisolitons in the sliding of hard incommensurate crystals is contrasted with the soliton-antisoliton pair nucleation at the large static friction threshold when the two lattices are commensurate and pinned. The frictional work can be directly extracted from particles' velocities and analysed as a function of classic tribological parameters, including speed, spacing and amplitude of the periodic potential (representing respectively the mismatch of the sliding interface, and the corrugation, or ``load''). These and other features suggestive of further experiments and insights promote colloid sliding to a novel friction study instrument. [1] T. Bohlein et al, Nat. Mat. 11, 126 (2012) [2] A. Vanossi et al, PNAS 109, 16429 (2012) 109:-16433 |
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