Scaling the Temperature-dependent Boson Peak of Vitreous Silica with the high-frequency Bulk Modulus derived from Brillouin Scattering Data

TL;DR

This study investigates how the boson peak in vitreous silica varies with temperature by analyzing high-frequency bulk modulus data from Brillouin scattering, revealing a link to the soft-potential model.

Contribution

It introduces a new temperature-dependent analysis of the boson peak using bulk modulus from Brillouin scattering, connecting structural evolution to soft-potential energy scales.

Findings

Scaling exponents align with the soft-potential model.

Unrelaxed bulk modulus effectively tracks silica's structural changes with temperature.

The bulk modulus sets the energy scale for soft potentials in silica.

Abstract

The position and strength of the boson peak in silica glass vary considerably with temperature $T$. Such variations cannot be explained solely with changes in the Debye energy. New Brillouin scattering measurements are presented which allow determining the $T$-dependence of unrelaxed acoustic velocities. Using a velocity based on the bulk modulus, scaling exponents are found which agree with the soft-potential model. The unrelaxed bulk modulus thus appears to be a good measure for the structural evolution of silica with $T$ and to set the energy scale for the soft potentials.