Spiral Evolution in a Confined Geometry

TL;DR

This paper investigates the dynamics of spiral evolution in nanoscale lead crystallites confined within a circular geometry, combining experimental STM observations with classical curvature-driven models to understand their relaxation behavior.

Contribution

It introduces a model that accurately describes the nonuniform spiral step evolution on confined nanoscale crystallites, integrating boundary conditions and curvature effects.

Findings

STM observations reveal nonuniform rotation and shape of spiral steps.

Classical curvature-driven models can be adapted to confined geometries.

The model successfully predicts the relaxation dynamics of the spiral steps.

Abstract

Supported nanoscale lead crystallites with a step emerging from a non-centered screw dislocation on the circular top facet were prepared by rapid cooling from just above the melting temperature. STM observations of the top facet show a nonuniform rotation rate and shape of the spiral step as the crystallite relaxes. These features can be accurately modeled using curvature driven dynamics, as in classical models of spiral growth, with boundary conditions fixing the dislocation core and regions of the step lying along the outer facet edge.