Resonant diffusion on solid surfaces

TL;DR

This paper introduces a new theoretical approach to understanding how atomic clusters diffuse on solid surfaces, emphasizing the non-monotonous, resonant dependence of diffusion on surface-cluster interactions and vibrations.

Contribution

It develops a model accounting for cluster vibrations and their impact on diffusion, providing a more comprehensive understanding of resonant diffusion phenomena.

Findings

Diffusion coefficient depends non-monotonously on surface-cluster fit

Cluster vibrations significantly influence surface mobility

Resonant diffusion exhibits complex behavior due to internal cluster dynamics

Abstract

A new approach to Brownian motion of atomic clusters on solid surfaces is developed. The main topic discussed is the dependence of the diffusion coefficient on the fit between the surface static potential and the internal cluster configuration. It is shown this dependence is non-monotonous, which is the essence of the so-called resonant diffusion. Assuming quicker inner motion of the cluster than its translation, adiabatic separation of these variables is possible and a relatively simple expression for the diffusion coefficient is obtained. In this way, the role of cluster vibrations is accounted for, thus leading to a more complex resonance in the cluster surface mobility.