Tuning friction to a superlubric state via in-plane straining

作者：Shuai Zhang, Yuan Hou, Suzhi Li, Luqi Liu, Zhong Zhang, Xi‐Qiao Feng, Qunyang Li · 发表于：Proceedings of the National Academy of Sciences · 年份：2019 · DOI：10.1073/pnas.1907947116 · 被引用次数：137 · 研究领域：Force Microscopy Techniques and Applications、Graphene research and applications、Diamond and Carbon-based Materials Research

Controlling, and in many cases minimizing, friction is a goal that has long been pursued in history. From the classic Amontons-Coulomb law to the recent nanoscale experiments, the steady-state friction is found to be an inherent property of a sliding interface, which typically cannot be altered on demand. In this work, we show that the friction on a graphene sheet can be tuned reversibly by simple mechanical straining. In particular, by applying a tensile strain (up to 0.60%), we are able to achieve a superlubric state (coefficient of friction nearly 0.001) on a suspended graphene. Our atomistic simulations together with atomically resolved friction images reveal that the in-plane strain effectively modulates the flexibility of graphene. Consequently, the local pinning capability of the contact interface is changed, resulting in the unusual strain-dependent frictional behavior. This work demonstrates that the deformability of atomic-scale structures can provide an additional channel of regulating the friction of contact interfaces involving configurationally flexible materials.