Molecular Dynamics Simulation of Friction in Xenon Films on a Silver Substrate

TL;DR

This study uses molecular dynamics simulations to analyze friction behavior of xenon films on silver substrates, revealing coverage-dependent slip times and phonon-dominated friction mechanisms.

Contribution

It introduces a simulation approach to quantify slip times and explores the coverage-dependent friction behavior of Xe films on Ag(111).

Findings

Slip time drops then sharply increases near one monolayer coverage.

Friction is dominated by phonon excitations.

Simulation results agree with experimental observations.

Abstract

We perform molecular dynamics simulations of friction for atomically thin Xe films sliding on Ag(111). We determine the inverse of the coefficient of friction (i.e. slip time) by direct calculation of the decay of the center of mass velocity after applying an external force, as well as from the velocity autocorrelation function. We find that the slip time exhibits a drop followed by a sharp increase in a range of coverage near one monolayer. The slip time then levels off with further coverage increases in agreement with previously reported experiments. Our simulations suggest that the friction found in this system is dominated by phonon excitations.