Acoustic Nature of the Boson Peak in Vitreous Silica

TL;DR

This study compares temperature-dependent inelastic x-ray, Raman, and neutron scattering data in vitreous silica, providing evidence that the boson peak originates from acoustic vibrational modes.

Contribution

It presents new temperature-dependent scattering data and demonstrates the acoustic nature of the boson peak in vitreous silica.

Findings

IXS data show collective excitations up to Q=3.5 nm^-1

The temperature behavior of excitations at Q=1.6 nm^-1 matches the boson peak

Supports the acoustic origin of the boson peak in vitreous silica

Abstract

New temperature dependent inelastic x-ray (IXS) and Raman (RS) scattering data are compared to each other and with existing inelastic neutron scattering data in vitreous silica (v-SiO_2), in the 300 - 1775 K region. The IXS data show collective propagating excitations up to Q=3.5 nm^-1. The temperature behaviour of the excitations at Q=1.6 nm^-1 matches that of the boson peak found in INS and RS. This supports the acoustic origin of the excess of vibrational states giving rise to the boson peak in this glass.