Complex shape evolution of electromigration-driven single-layer islands

TL;DR

This paper investigates how electromigration and crystal anisotropy influence the shape evolution of 2D islands, revealing complex migration modes and phase diagrams through numerical and analytical methods.

Contribution

It introduces a continuum model incorporating crystal anisotropy to analyze diverse migration behaviors and constructs a phase diagram of island dynamics.

Findings

Anisotropy induces oscillatory and irregular migration modes.

Stable facets develop on islands, explaining oscillatory motion.

Analytical determination of facet orientations.

Abstract

The shape evolution of two-dimensional islands through periphery diffusion biased by an electromigration force is studied numerically using a continuum approach. We show that the introduction of crystal anisotropy in the mobility of edge atoms induces a rich variety of migration modes, which include oscillatory and irregular behavior. A phase diagram in the plane of anisotropy strength and island size is constructed. The oscillatory motion can be understood in terms of stable facets which develop on one side of the island and which the island then slides past. The facet orientations are determined analytically.