Stability of a strongly anisotropic thin epitaxial film in a wetting interaction with elastic substrate

TL;DR

This paper extends the linear stability analysis of thin epitaxial films by incorporating surface energy anisotropy, revealing complex stability behaviors influenced by wetting interactions and anisotropy strength.

Contribution

It introduces a generalized dispersion relation accounting for surface energy anisotropy with variable strength, enhancing understanding of film stability under different conditions.

Findings

Strong anisotropy and wetting interactions lead to complex stability characteristics.

Wetting interaction alone can cause instability in films.

Surface energy anisotropy significantly influences film morphology stability.

Abstract

The linear dispersion relation for longwave surface perturbations, as derived by Levine et al. Phys. Rev. B 75, 205312 (2007) is extended to include a smooth surface energy anisotropy function with a variable anisotropy strength (from weak to strong, such that sharp corners and slightly curved facets occur on the corresponding Wulff shape). Through detailed parametric studies it is shown that a combination of a wetting interaction and strong anisotropy, and even a wetting interaction alone results in complicated linear stability characteristics of strained and unstrained films. PACS: 68.55.J, Morphology of films; 81.15.Aa, Theory and models of film growth; 81.16.Dn, Self-assembly.