Predicting the lifetime of superlubricity

¹ School of Mechanical Engineering, Southwest Jiaotong University - Chengdu 610031, China
² Applied Mechanics Laboratory, Department of Engineering Mechanics and Center for Nano and Micro Mechanics, Tsinghua University - Beijing 100084, China
³ Université Pairs-Est, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS 5 Bd Descartes, 77454 Marne-la-Valleé Cedex 2, France

^(a) qi-chang.he@univ-paris-est.fr
^(b) xuzp@tsinghua.edu.cn

Received: 25 September 2015
Accepted: 23 December 2015

Abstract

The concept of superlubricity has recently called upon notable interest after the demonstration of ultralow friction between atomistically smooth surfaces in layered materials. However, the energy dissipation process conditioning the sustainability of a superlubric state has not yet been well understood. In this work, we address this issue by performing dynamic simulations based on both full-atom and reduced Frenkel-Kontorova models. We find that the center-of-mass momentum autocorrelation of a sliding object can be used as a statistical indicator of the state of superlubricity. Beyond a critical value of it, the sliding motion experiences a catastrophic breakdown with a dramatically high rate of energy dissipation, caused by the inter-vibrational-mode coupling. By tracking this warning signal, one can extract heat from modes other than the translation to avoid the catastrophe and extend the lifetime of superlubricity. This concept is demonstrated in double-walled carbon-nanotubes–based nanomechanical devices with the indicator-based feedback design implemented.