Nucleation and step-edge barriers always destabilize step-flow growth of a vicinal surface

TL;DR

This paper demonstrates that nucleation and step-edge barriers inherently destabilize step-flow growth on vicinal surfaces, showing metastability regardless of barrier strength due to critical nucleus formation.

Contribution

It reveals that step-flow growth is always metastable with nucleation effects, challenging previous theories suggesting stability at low barriers.

Findings

Step-flow growth is metastable for any step-edge barrier strength.

Critical nucleus formation leads to surface destabilization.

Previous models predicting stability at low barriers are insufficient.

Abstract

We consider the effect of nucleation on a one-dimensional stepped surface, finding that step-flow growth is metastable for any strength of the additional step-edge barrier. The surface is made unstable by the formation of a critical nucleus, whose lateral size is related to the destabilization process on a high-symmetry surface. Arguments based on a critical nucleus of height two, which suggest the existence of a fully stable regime for small barrier, fail to describe this phenomenon.