Atomistic simulations of the sliding friction of graphene flakes

TL;DR

This paper uses advanced atomistic simulations to study the sliding friction of graphene flakes, incorporating quantum mechanics and flake flexibility, providing insights consistent with experimental results.

Contribution

It introduces a fully-atomistic, quantum-mechanical model that accounts for flake flexibility and rotation, improving upon previous rigid, idealized models.

Findings

Flake rotation significantly affects static friction.

Quantum mechanical effects influence bond dynamics during sliding.

Results align qualitatively with experimental observations.

Abstract

Using a tight-binding atomistic simulation, we simulate the recent atomic-force microscopy experiments probing the slipperiness of graphene flakes made slide against a graphite surface. Compared to previous theoretical models, where the flake was assumed to be geometrically perfect and rigid, while the substrate is represented by a static periodic potential, our fully-atomistic model includes quantum mechanics with the chemistry of bond breaking and bond formation, and the flexibility of the flake. These realistic features, include in particular the crucial role of the flake rotation in determining the static friction, in qualitative agreement with experimental observations.