|Atomic-Spring-like Effect in Glassy Silica-Helium Composites br |
(Article) Publié: The Journal Of Physical Chemistry C, vol. 126 p.5722-5727 (2022)
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We determine the structural origin of an “atomic-spring-like effect”in a glassy silica-helium composite, which exhibits this mechanical property thatreversibly accumulates and restores energy at the subnanoscale based on a high-pressure experimental pair distribution function study combined with atom-scalemolecular simulations. These unexpected experimental results were obtained byusing a 3 μm spot size 61 keV X-ray beam and large area detector and bysubtracting the scattered intensity due to helium outside the sample from the silicasignal at the same focal point for each pressure point. The compression behavior ofthe glassy silica-helium composite is characterized on a structural level by the change from a uni- to bimodal distribution in the inter- tetrahedral distances in the amorphous isotropic structure of silica. We propose a simple characterization of this atomic-spring-like glass property using impedance spectroscopy measurements.