In an effort to reduce the friction between sliding components scientists and engineers have developed a multitude of lubrication schemes. One of the most intriguing concepts is referred to as `structural lubricity', where flat surfaces are thought to slide past each other virtually frictionless if their atomic structures are incommensurate. In this talk, we analyze the fundamental mechanisms that govern the area-dependence of friction in extended but atomically flat contacts of dissimilar materials with a particular emphasize on the relation between structure (crystalline vs. amorphous) and friction. The resulting sublinear power laws, which link mesoscopic friction to atomic principles, are then confirmed by measuring the sliding resistance of gold and antimony particles on graphite [1,2]. The findings suggest that engineering surfaces with unprecedented low friction can be realized.

[1] A. Schirmeisen and U. D. Schwarz, ChemPhysChem 10 (2009) 2358

[2] D. Dietzel et al., Physical Review Letters 101 (2008) 125505