Large and realistic models of Amorphous Silicon

TL;DR

This paper evaluates large, realistic amorphous silicon models, demonstrating that the FEAR algorithm accurately reproduces experimental structural data and highlights the importance of large models for vibrational and thermal property analysis.

Contribution

The study introduces large, realistic amorphous silicon models using the FEAR algorithm, showing improved agreement with experimental data and emphasizing the need for large models for vibrational properties.

Findings

FEAR algorithm yields results consistent with experimental diffraction data.

Large models (500 atoms) are essential for accurate vibrational and thermal properties.

Computed density matches experimental measurements.

Abstract

Amorphous silicon (a-Si) models are analyzed for structural, electronic and vibrational characteristics. Several models of various sizes have been computationally fabricated for this analysis. It is shown that a recently developed structural modeling algorithm known as force-enhanced atomic refinement (FEAR) provides results in agreement with experimental neutron and x-ray diffraction data while producing a total energy below conventional schemes. We also show that a large model (500 atoms) and a complete basis is necessary to properly describe vibrational and thermal properties. We compute the density for a-Si, and compare with experimental results.