Density-functional theory calculations of hopping rates of surface diffusion

TL;DR

This study uses density-functional theory to calculate surface diffusion rates of silver on different substrates, revealing that simple scaling laws may not reliably predict diffusion parameters.

Contribution

It provides detailed first-principles calculations of energy barriers and attempt frequencies for surface diffusion, challenging existing assumptions about scaling laws.

Findings

Attempt frequency around 1 THz for all systems

Simple scaling laws often do not apply to diffusion parameters

Contradicts the compensation effect and recent experimental results

Abstract

Using density-functional theory we compute the energy barriers and attempt frequencies for surface diffusion of Ag on Ag(111) with different lattice constants, and on an Ag adsorbate monolayer on Pt(111). We find that the attempt frequency is of the order of 1 THz for all the systems studied. This is in contrast to the so-called compensation effect, and to recent experimental studies. Our analysis suggests that the applicability of simple (commonly used) scaling laws for the determination of diffusion and growth parameters is often not valid.