The Boson Peak and its Relation with Acoustic Attenuation in Glasses

TL;DR

This paper compares experimental data on vibrational states and acoustic modes in glasses with theoretical models, highlighting that models including non-acoustic vibrational modes better explain glass anomalies than elastic instability models.

Contribution

It demonstrates that models incorporating non-acoustic vibrational modes at THz frequencies align well with experimental observations, advancing understanding of glass vibrational properties.

Findings

Elastic instability models fail to explain most observations.

Models with non-acoustic vibrational modes show good agreement with experiments.

Provides a comprehensive picture of glass anomalies in the THz region.

Abstract

Experimental results on the density of states and on the acoustic modes of glasses in the THz region are compared to the predictions of two categories of models. A recent one, solely based on an elastic instability, does not account for most observations. Good agreement without adjustable parameters is obtained with models including the existence of non-acoustic vibrational modes at THz frequency, providing in many cases a comprehensive picture for a range of glass anomalies.