Effect of surface roughness and adsorbates on superlubricity.pdf

Effect of surface roughness and adsorbates on superlubricity V.N. Samoilov,1,2 C. Yang,1 U. Tartaglino,1,3 and B.N.J. Persson1 1IFF, FZ-J¨ulich, 52425 J¨ulich, Germany 2Physics Faculty, Moscow State University, 117234 Moscow, Russia 3Democritos National Simulation Center, Via Beirut 2, 34014 Trieste, Italy 7 We study the sliding of elastic solids in adhesive contact with flat and rough interfaces. We 0 consider the dependence of the sliding friction on the elastic modulus of the solids. For elastically 0 hard solids with planar surfaces with incommensurate surface structures we observe extremely low 2 friction (superlubricity), which very abruptly increases as the elastic modulus decreases. We show that even a relatively small surface roughness or a low concentration of adsorbates may completely r p kill the superlubricity state. This manuscript has been published in the book: “Superlubricity”, edited by A. Erdemir and A J.-M. Martin, Elsevier, Amsterdam (2007). The copyright of the final version of this paper has been 8 tranferred to Elsevier. 2 ] 1. Introduction solids. In this case there is a competition between two t f energies: the lateral corrugation of the interaction po- o Friction between solid surfaces is a very important phe- tential between the walls, and the elastic energy to de- s. nomenon for bi