Key Issues of Nanotribology for Successful Nanofabrication – From Basis to C60 Molecular Bearings

Abstract

We briefly review the key issues of nanotribology, particularly the mechanism of friction on graphite surface, i.e., atomic friction, flake friction, and C₆₀ molecular bearings. For the atomic and flake frictions, frictional force maps are compared between simulations and experiments, which can be explained by stick-slip motion of the tip apex atom and flake. For C₆₀ molecular bearings, a novel frictional mechanism realized in the graphite/C₆₀ ^mono/graphite system, is reported. In this system, static frictional forces have a finite value but denote that dynamical frictional forces are zero. In order to explain the mechanism, “step rotation model” of a C₆₀ molecule is proposed by considering the effect of thermal activation, based on the concept of “single-molecular bearings.” It should be emphasized that the graphite/C₆₀ ^mono/graphite system is the smallest bearing in the world which has a tremendous potential for the realization of nano- and micro-machines, and has opened a new field of molecular bearings.