MICROSCOPIC MECHANISMS FOR KINETIC FRICTION - NEARLY FRICTIONLESS SLIDING FOR SMALL SOLIDS

In previous work, the present author presented calculations in support of the contention that the long-time average rate of energy dissipati on that occurs when two sufficiently small nonmetallic solid bodies sl ide in contact with each other in steady state is nearly zero. This ph enomenon is believed to be due to the lack of ergodicity found in mode l calculations by Fermi, Pasta, and Ulam. In this paper, similar calcu lations will be presented on a square and a triangular lattice, whose atoms interact with a truncated Lennard-Jones potential, sliding with one edge in contact with both periodic and disordered potentials (due to a second two-dimensional solid in which it is in contact) at both z ero and nonzero temperature, which support this idea. These new result s are discussed using scaling arguments and in conjunction with result s on the interaction of the sample with a solid which supports it, as well as with the atmosphere, in order to make estimates of the experim ental conditions under which extremely low dissipation should be obser vable in real mesoscopic solids. The calculations at nonzero temperatu re support the contention that this phenomenon could occur at reasonab ly high fraction of the melting temperature if the solid is sufficient ly small.