Thermal effects and spontaneous frictional relaxation in atomically thin layered materials

TL;DR

This paper explores how thermal effects influence frictional behavior and contact aging in atomically thin layered materials through simulations and analytical models, revealing slower aging dynamics than previously understood.

Contribution

It introduces a simple Prandtl-Tomlinson based model that captures layer-dependent friction and aging effects, aligning with experimental observations and providing new insights into contact relaxation.

Findings

Contact aging is slower than exponential decay.

Thermal effects weaken the contact over time.

Model predictions are consistent with AFM experiments.

Abstract

We study the thermal effects on the frictional properties of atomically thin sheets. We simulate a simple model based on the Prandtl-Tomlinson model that reproduces the layer dependence of friction and strengthening effects seen in AFM experiments. We investigate sliding at constant speed as well as reversing direction. We also investigate contact aging: the changes that occur to the contact when the sliding stops completely. We compare the numerical results to analytical calculations based on Kramers rates. We find that there is a slower than exponential contact aging that weakens the contact and that we expect will be observable in experiments. We discuss the implications for sliding as well as aging experiments.