Non-equilibrium surface diffusion in the O/W(110) system

TL;DR

This study uses Monte Carlo simulations to analyze non-equilibrium surface diffusion of oxygen on tungsten (110), focusing on adatom mobility and fluctuations, and compares findings with experimental data.

Contribution

It provides a detailed Monte Carlo analysis of non-equilibrium diffusion in the O/W(110) system, introducing effective, time-dependent diffusion mobilities.

Findings

Effective diffusion barriers are characterized under non-equilibrium conditions.

Mobility measures evolve over time and differ from equilibrium diffusion constants.

The study highlights challenges in interpreting non-equilibrium diffusion data.

Abstract

In this Letter, we present results of an extensive Monte Carlo study of the O/W(110) system under non-equilibrium conditions. We study the mean square displacements and long wavelength density fluctuations of adatoms. From these quantities, we define effective and time-dependent values for the collective and tracer diffusion mobilities. These mobilities reduce to the usual diffusion constants when equilibrium is reached. We discuss our results in view of existing experimental measurements of effective diffusion barriers, and the difficulties associated with interpreting non-equilibrium data.