Structural lubricity: Role of dimension and symmetry

PACS. 68.35.Af – Atomic scale friction. PACS. 81.40.Pq – Friction, lubrication, and wear. Abstract. – When two chemically passivated solids are brought into contact, interfacial interactions between the solids compete with intrabulk elastic forces. The relative importance of these interactions, which are length-scale dependent, will be estimated using scaling arguments. If elastic interactions dominate on all length scales, solids will move as essentially rigid objects. This would imply superlow kinetic friction in UHV, provided wear was absent. The results of the scaling study depend on the symmetry of the surfaces and the dimensionalities of interface and solids. Some examples are discussed explicitly such as contacts between disordered threedimensional solids and linear bearings realized from multiwall carbon nanotubes. Introduction. – Many small-scale devices cannot be miniaturized further, because friction and wear appear to be exceedingly large in nanoscale machines. This limitation seems to arise, because the surface to volume ratio is large in small systems and thus surface forces such as friction become relatively large. However, many theoretical studies 1, 2, 3, 4, 5 and most recently an increasing number of experiments 6,7,8,9,10,11 indicate that shear forces can