Nearly defect-free dynamical models of disordered solids: The case of amorphous silicon

TL;DR

This paper demonstrates the creation of nearly defect-free, large-scale amorphous silicon models using classical molecular dynamics, matching experimental data and surpassing previous MD-based models in quality.

Contribution

It introduces a novel approach to generate high-quality, defect-free amorphous silicon models with up to half a million atoms via classical MD simulations.

Findings

Models match experimental structural and electronic data

Models are comparable to those from bond-switching algorithms

Achieved the highest quality amorphous silicon models via MD

Abstract

It is widely accepted in the materials modeling community that defect-free realistic networks of amorphous silicon cannot be prepared by quenching from a molten state of silicon using classical or ab initio molecular-dynamics (MD) simulations. In this work, we address this long-standing problem by producing nearly defect-free ultra-large models of amorphous silicon, consisting of up to half-a-million atoms, using classical molecular-dynamics simulations. The structural, topological, electronic, and vibrational properties of the models are presented and compared with experimental data. A comparison of the models with those obtained from using the modified Wooten-Winer-Weaire bond-switching algorithm shows that the models are on par with the latter, which were generated via event-based total-energy relaxations of atomistic networks in the configuration space. The MD models produced in this work represent the highest quality of amorphous-silicon networks so far reported in the literature using molecular-dynamics simulations.