Atomic-Spring-like Effect in Glassy Silica-Helium Composites

We determine the structural origin of an atomic-spring-like effect in a glassy silica-helium composite, which exhibits this mechanical property that reversibly 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 mu m 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 of the 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

Automated summary

In this study, the structural origin of the atomic-spring-like effect in a glassy silica-helium composite is determined using a combination of high-pressure experimental pair distribution function study and atom-scale molecular simulations. The reversible accumulation and restoration of energy at the subnanoscale is observed, and the compression behavior is characterized by a change in the inter-tetrahedral distances in the amorphous isotropic structure of silica. Impedance spectroscopy measurements provide a simple characterization of this unique glass property.