Effect of step stiffness and diffusion anisotropy on the meandering of a growing vicinal surface

TL;DR

This paper investigates how step stiffness and diffusion anisotropy influence the meandering instability of vicinal surfaces, revealing a finite wavelength instability governed by the conserved Kuramoto-Sivashinsky equation with coarsening behavior.

Contribution

It introduces a model linking diffusion anisotropy and step stiffness to surface meandering, highlighting the conditions for instability and the resulting coarsening dynamics.

Findings

Finite wavelength instability depends on flux and stiffness difference.

Meander dynamics follow the conserved Kuramoto-Sivashinsky equation.

Surface coarsening observed over time.

Abstract

We study the step meandering instability on a surface characterized by the alternation of terraces with different properties, as in the case of Si(001). The interplay between diffusion anisotropy and step stiffness induces a finite wavelength instability corresponding to a meandering mode. The instability sets in beyond a threshold value which depends on the relative magnitudes of the destabilizing flux and the stabilizing stiffness difference. The meander dynamics is governed by the conserved Kuramoto-Sivashinsky equation, which display spatiotemporal coarsening.