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MM: Fachverband Metall- und Materialphysik

MM 55: Liquid and Amorphous Materials II

MM 55.1: Talk

Thursday, March 21, 2024, 10:15–10:30, C 230

Between amorphous and crystalline silicon: a revised paracrystalline model — •Louise A. M. Rosset and Volker L. Deringer — Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, Oxford, UK

The existence of paracrystalline silicon, characterized as a crystallite embedded in an amorphous matrix, has long been a topic of debate; the argument derives from hand crafted models and a limited exploration of configurational space, restricted by slow, inaccessible quench rates.

Using a computationally efficient machine-learning potential that unlocks slow quench rates comparable to experiment, we systematically sample the space of a-Si structures by simulated melt-quenching and build a large dataset of disordered silicon configurations. This extensive database points toward the existence of `paracrystalline' disordered structures, characterized by localized diamond-like neighborhoods that affect medium-range properties. These configurations vary widely in structure and energy, and demonstrate better agreement with experimental results than previously proposed models.

This work highlights the use of data driven methods in elucidating fundamental structural questions using systematic sampling of the configurational space.

Keywords: amorphous silicon; ML potential; structural analysis