Frictional Dissipation and Scaling Laws at van der Waals Interfaces: The Role of Edge and Corner Elastic Moiré Pinning.

Abstract

van der Waals heterogeneous interfaces are promising candidates for the scaling-up of structural superlubricity to meet a wide range of applications. Several factors, however, have been identified that may hinder superlubricity. Elasticity is one such intrinsic factor, where shear induced lattice reconstruction leads to local interfacial pinning, even at clean pristine contacts. This introduces intricate energy dissipation mechanisms that are manifested by unconventional frictional scaling laws. Here, through large-scale atomistic simulations, we reveal that the elastic pinning of incomplete moiré tiles at the corners of polygonal sliders dominates kinetic friction up to contact dimensions of hundreds of nanometers, followed by a crossover to edge, and eventually surface dominated frictional regimes. We further demonstrate that slider shape tailoring and twisting allow to control energy dissipation and its scaling with contact size, thus advancing the quest toward achieving large-scale superlubricity.