Abstract
The frictional behavior of supported graphene is known to be influenced by the physical properties and surface morphologies of the underlying substrate.However,it is unclear how a surface defect on the substrate affects the friction of supported graphene,and it is even unknown how to define the defect-induced friction force in this context.Here we conduct molecular dynamics(MD)simulations to investigate the friction between a square diamond slider and a graphene sheet supported by a copper substrate with a surface cavity defect.Our results demonstrate that the defect-induced friction exhibits a nonlinear increase with cavity size,while it decreases nonlinearly with slider size.We propose that the definition of defect-induced friction can be linked to the increase in friction work over the length of the slider,and is closely correlated to the defect-induced relative change in indentation depth and the ratio of the cavity area to the contact area.These findings provide a comprehensive evaluation of the impact of a substrate cavity defect on the friction of supported graphene and offer insights that may have broader implications for understanding defect-induced friction in other two-dimensional materials.
基金项目
National Natural Science Foundation of China(12132008)
Key Research Project of Zhejiang Laboratory(2021PE0AC02)
万方数据