Electromigration-Induced Flow of Islands and Voids on the Cu(001) Surface

TL;DR

This study investigates how electromigration causes the movement of islands and voids on the Cu(001) surface at the atomic level, identifying key mechanisms and energy barriers through simulations.

Contribution

It provides a detailed atomic-scale analysis of electromigration-induced flow on Cu(001), including energy barriers and dominant diffusion mechanisms, using kinetic Monte Carlo simulations.

Findings

Edge diffusion is the main mass-transport mechanism.

Detachment from corners is the rate-limiting step.

Energy barriers align with activation energies from Arrhenius analysis.

Abstract

Electromigration-induced flow of islands and voids on the Cu(001) surface is studied at the atomic scale. The basic drift mechanisms are identified using a complete set of energy barriers for adatom hopping on the Cu(001) surface, combined with kinetic Monte Carlo simulations. The energy barriers are calculated by the embedded atom method, and parameterized using a simple model. The dependence of the flow on the temperature, the size of the clusters, and the strength of the applied field is obtained. For both islands and voids it is found that edge diffusion is the dominant mass-transport mechanism. The rate limiting steps are identified. For both islands and voids they involve detachment of atoms from corners into the adjacent edge. The energy barriers for these moves are found to be in good agreement with the activation energy for island/void drift obtained from Arrhenius analysis of the simulation results. The relevance of the results to other FCC(001) metal surfaces and their experimental implications are discussed.