Adatom-induced dislocation annihilation in epitaxial silicene

TL;DR

This study investigates how silicon adatoms induce dislocation annihilation in epitaxial silicene, revealing mechanisms of defect healing and domain formation in two-dimensional honeycomb structures through real-time STM analysis.

Contribution

It uncovers the stepwise dislocation reactions and nucleation processes leading to single-domain silicene, advancing understanding of defect healing in 2D materials.

Findings

Dislocation nucleation occurs via partial dislocation reactions.

Single-domain silicene extends through edge dislocation propagation.

Adatom adsorption facilitates dislocation annihilation and defect healing.

Abstract

The transformation of the stripe domain structure of spontaneously-formed epitaxial silicene on ZrB$_2$ thin film into a single-domain driven by the adsorption of a fraction of a monolayer of silicon was used to investigate how dislocations react and eventually annihilate in a two-dimensional honeycomb structure. The in-situ real time STM monitoring of the evolution of the domain structure after Si deposition revealed the mechanisms leading to the nucleation of a single-domain into a domain structure through a stepwise reaction of partial dislocations. After its nucleation, the single-domain extends by the propagation of edge dislocations at its frontiers. The identification of this particular nucleation-propagation formation of dislocation-free silicene sheet provides insights into how crystallographic defects can be healed in two-dimensional materials.