Inhomogeneous elastic response of silica glass

TL;DR

This study uses large-scale molecular dynamics simulations to analyze the elastic inhomogeneities in silica glass, revealing a characteristic length scale where classical elasticity fails, and linking it to the Boson-peak anomaly.

Contribution

It identifies a specific length scale in silica glass that characterizes elastic correlations and compares it with fragile glasses, advancing understanding of amorphous solids' elastic properties.

Findings

Existence of a correlation length scale   about 1000 atoms.

Elastic inhomogeneities are linked to the Boson-peak anomaly.

Classical elasticity breaks down below the length scale  .

Abstract

Using large scale molecular dynamics simulations we investigate the properties of the {\em non-affine} displacement field induced by macroscopic uniaxial deformation of amorphous silica,a strong glass according to Angell's classification. We demonstrate the existence of a length scale $\xi$ characterizing the correlations of this field (corresponding to a volume of about 1000 atoms), and compare its structure to the one observed in a standard fragile model glass. The "Boson-peak'' anomaly of the density of states can be traced back in both cases to elastic inhomogeneities on wavelengths smaller than $\xi$, where classical continuum elasticity becomes simply unapplicable.