Depth-dependent critical behavior in V2H

TL;DR

This study investigates how inhomogeneous defect distributions in V2H's surface layer cause a depth-dependent phase transition, revealing a novel critical behavior influenced by defect density variations.

Contribution

It introduces a depth-dependent scaling law to describe critical behavior in a defective surface layer with inhomogeneous dislocation distribution.

Findings

Critical temperature varies with depth due to defect density.

A new depth-dependent scaling law models the critical behavior.

Dislocation walls influence phase transition properties.

Abstract

Using X-ray diffuse scattering, we investigate the critical behavior of an order-disorder phase transition in a defective "skin-layer" of V2H. In the skin-layer, there exist walls of dislocation lines oriented normal to the surface. The density of dislocation lines within a wall decreases continuously with depth. We find that, because of this inhomogeneous distribution of defects, the transition effectively occurs at a depth-dependent local critical temperature. A depth-dependent scaling law is proposed to describe the corresponding critical ordering behavior.