Simulations of the Anisotropy of Friction Force between a Silicon Tip and a Substrate at Nano-scale

摘要

In this paper,the anisotropy of the friction force with the variety of rotation angle between a silicon tip and a substrate was investigated using molecular dynamics simulations.When the silicon tip sliding over the silicon substrate under incommensurate contacting surfaces,the results of simulations illustrate that the sliding friction forces decrease with the increase of rotation angle from 0°to 45°,and they increase with the increase of rotation angle from 45°to 90°.Further a approximate symmetrical curve of the friction force with respect to 45°angle can be obtained and at this angle the friction force is minimum and close to superlubricity.However,at the same angle the friction force is no more decrease with the increase of the temperature and its size mainly depends to the degree of the commensurability of the contacting surfaces instead of the temperature.