Year: 2024
Type: article
Abstract: Using a Lubachevsky–Stillinger-like growth algorithm combined with biased SWAP Monte Carlo and transient degrees of freedom, we generate ultradense disordered jammed ellipse packings. For all aspect ratios α, these packings exhibit significantly smaller intermediate-wavelength density fluctuations and greater local nematic order than their less-dense counterparts. The densest packings are disordered despite having packing fractions ϕ J (α) that are within less than 0.5% of that of the monodisperse-ellipse crystal [ϕ xtal = π/(2√3) ≃ 0.9069] over the range 1.2 ≲ α ≲ 1.45 and coordination numbers Z J (α) that are within less than 0.5% of isostaticity [ Z iso = 6] over the range 1.2 ≲ α ≲ 2.6. Lower-α packings are strongly fractionated and consist of polycrystals of intermediate-size particles, with the largest and smallest particles isolated at the grain boundaries. Higher-α packings are also fractionated, but in a qualitatively different fashion; they are composed─of increasingly large locally nematic domains─reminiscent of liquid glasses.
Author: Robert S. Hoy
Institution: University of South Florida
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
Funder: National Science Foundation
OpenAlex ID: W4405925447