Interface roughening with nonlinear surface tension

TL;DR

This paper proposes adding a nonlinear surface tension term to the KPZ equation, revealing an unstable fixed point for interface dimensions above approximately 3.3, with implications for interface roughening transitions.

Contribution

It introduces a nonlinear surface tension term into the KPZ equation and analyzes its effects using renormalization group methods, revealing new fixed point behavior.

Findings

Unstable strong-coupling fixed point for dimensions > 3.3

Nonlinear surface tension influences interface roughening

Implications for the roughening transition

Abstract

Using stability arguments, this Brief Report suggests that a term that enhances the surface tension in the presence of large height fluctuations should be included in the Kardar-Parisi-Zhang equation. A one-loop renormalization group analysis then shows for interface dimensions larger than $\simeq 3.3$ an unstable strong-coupling fixed point that enters the system from infinity. The relevance of these results to the roughening transition is discussed.