Temperature dependence of contact quality inducing suppression of stick-slip friction

Atomic-scale stick-slip friction of monolayer graphene on a copper substrate is computationally studied at a wide range of temperatures, which reveals strong temperature dependence of friction force and friction mode. The increase in temperature distorts regular stick-slip behavior and causes a nonlinear decrease of friction force, demonstrating a friction behavior transition from athermal friction to thermally activated. By analyzing atomic morphologies, the true contact area, defining the number of atoms interacting across the interface, shows a weak temperature dependence, yet the quality of interfacial contact substantially varies with temperature. Spatial distributions of atomic friction force uncover the significant effect of Moire superlattices, that act as strong pinning sites at low temperatures, partly change to pushing due to nonconcurrent atomic jumps at high temperatures, which leads to a chaotic friction mode with reduced lateral force. Additionally, we demonstrate the role of superlattices in strengthening friction and dictating the periodic stick-slip motion of interfacial sliding. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The computational study on the atomic-scale stick-slip friction of monolayer graphene on a copper substrate reveals a strong temperature dependence of friction force and friction mode. The role of Moire superlattices in affecting friction force is significant, especially at different temperatures, leading to changes in friction behavior and transition from athermal to thermally activated friction modes.