Structural simplicity as a restraint on the structure of amorphous silicon

Abstract

Understanding the structural origins of the properties of amorphous materials remains one of the most important challenges in structural science. In this study we demonstrate that local 'structural simplicity', embodied by the degree to which atomic environments within a material are similar to each other, is powerful concept for rationalising the structure of canonical amorphous material amorphous silicon (a-Si). We show, by restraining a reverse Monte Carlo refinement against pair distribution function (PDF) data to be simpler, that the simplest model consistent with the PDF is a continuous random network (CRN). A further effect of producing a simple model of a-Si is the generation of a (pseudo)gap in the electronic density of states, suggesting that structural homogeneity drives electronic homogeneity. That this method produces models of a-Si that approach the state-of-the-art without the need for chemically specific restraints (beyond the assumption of homogeneity) suggests that simplicity-based refinement approaches may allow experiment-driven structural modelling techniques to be developed for the wide variety of amorphous semiconductors with strong local order.

Citation

Cliffe, M. J., Bartók, A. P., Kerber, R. N., Grey, C. P., Csányi, G., & Goodwin, A. L. (2017). Structural simplicity as a restraint on the structure of amorphous silicon. Physical Review B, 95(22), Article 224108. https://doi.org/10.1103/physrevb.95.224108

• Journal Article Type: Article
• Acceptance Date: Jun 30, 2017
• Online Publication Date: Jun 30, 2017
• Publication Date: Jun 30, 2017
• Deposit Date: Dec 20, 2018
• Publicly Available Date: Dec 20, 2018
• Journal: Physical Review B
• Print ISSN: 2469-9950
• Electronic ISSN: 2469-9969
• Publisher: American Physical Society
• Peer Reviewed: Peer Reviewed
• Volume: 95
• Issue: 22
• Article Number: 224108
• DOI: https://doi.org/10.1103/physrevb.95.224108
• Public URL: https://nottingham-repository.worktribe.com/output/1430928
• Publisher URL: https://journals.aps.org/prb/pdf/10.1103/PhysRevB.95.224108
• Additional Information: Accepted version deposited on arXiv https://arxiv.org/abs/1609.00668