Identification of relaxation and diffusion mechanisms in amorphous silicon

TL;DR

This study uses the activation-relaxation technique to analyze over 8000 relaxation and diffusion events in amorphous silicon, revealing their properties, classification, and dominant mechanisms, consistent with experimental data.

Contribution

It provides a comprehensive database and classification of relaxation events in amorphous silicon, identifying key mechanisms involving four-fold coordinated atoms.

Findings

Properties of relaxation events align with experimental data

Introduction of a topological defect classification system

Identification of three dominant mechanisms for four-fold coordinated atoms

Abstract

The dynamics of amorphous silicon at low temperatures can be characterized by a sequence of discrete activated events, through which the topological network is locally reorganized. Using the activation-relaxation technique, we create more than 8000 events, providing an extensive database of relaxation and diffusion mechanisms. The generic properties of these events - size, number of atoms involved, activation energy, etc. - are discussed and found to be compatible with experimental data. We introduce a complete and unique classification of defects based on their topological properties and apply it to study of events involving only four-fold coordinated atoms. For these events, we identify and present in detail three dominant mechanisms.