Phonon propagation scale and nanoscale order in vitreous silica from Raman spectroscopy

TL;DR

This study uses Raman spectroscopy to determine the nanoscale phonon propagation length and order in vitreous silica, revealing a propagation scale of 0.5-2 nm, which enhances understanding of nanoscale vibrational properties.

Contribution

It demonstrates how Raman spectral analysis can be used to estimate phonon confinement and propagation scales in vitreous silica, providing new insights into its nanoscale order.

Findings

Phonon propagation scale in vitreous silica is 0.5-2 nm.

Raman spectra reflect localized phonons and nanoscale order.

Spectral convergence depends on confinement size.

Abstract

For nanoscale systems such as nanoparticles and 3D-bonded networks, the range of spatial coherence is well reflected in the Raman spectral pattern. For confined, or localized, phonons, the range of q-points contributing to the spectrum depends on the phonon confinement length, which makes possible to derive the size information from the spectra. In this work, Raman spectrum of vitreous silica is described as localized phonons of SiO2 network. The convergence of the spectral pattern with the confinement size is studied. It is shown that the phonon propagation scale in vitreous silica is within the 0.5-2 nm range.