Atomic-scale friction image of graphite in atomic-force microscopy

We theoretically investigated the image of atomic-scale friction of graphite in atomic-force microscopy (AFM), based on numerical simulation for a static model. We performed systematic calculations of lateral force images of AFM aiming to clarify the effects of cantilever stiffness, scan direction, anisotropy of the cantilever, and surface deformation. The simulation is performed for a simple atomistic model with a single-atom tip connected with the cantilever spring scanned on a monolayer graphite surface. The process in which the conservative lateral force becomes a nonconservative frictional force is clarified. ‘‘Stick regions’’ of the tip atom are also discussed in relation to the cantilever stiffness. Calculated frictional-force image patterns are in good agreement with experimental ones. We also find the supercell frictional-force images and discuss their mechanisms. © 1996 The American Physical Society.