Friction between Si tip and (001)-2×1 surface: A molecular dynamics simulation Original Research Article

In order to investigate the friction between a Si tip and its (001)-2×1 surface by molecular-dynamics (MD) simulation, two schemes are adopted. In the first scheme the tip advances over the substrate each MD step while in the second scheme the tip advances every 1000 MD steps. It is found that if the tip and the substrate approach each other closely enough, for both schemes wear occurs via a slip-stick mechanism, but their details are different from each other. We present a detailed explanation for this phenomenon and conclude that the second scheme is more appropriate for the description of experimental situations. In addition, we find that the frictional properties depend on the sliding direction.