Molecular dynamics study of the friction properties for a Ge TIP-surface system

Abstract

The friction between a Ge tip and its (001)-(2 × 1) reconstructed surface is investigated by molecular dynamics (MD) simulation. It is found that when the tip and the substrate approach each other closely enough, a wear occurs under slip-stick way. At the same time, it is also found that a permanent damage occurs when the tip advances perpendicularly to the dimer rows of the surface, while such damage is not observed when the tip moves parallelly to the dimer rows. This is different from the friction phenomena on a macroscopic scale. At the microscopic level, the resulting atomic configuration and the properties of friction force vs. sliding distance depend strongly on a sliding direction.