The Boson Peak in Amorphous Silica: Results from Molecular Dynamics Computer Simulations

TL;DR

This study uses molecular dynamics simulations to analyze the boson peak in amorphous silica, revealing its origin as coupling to transverse acoustic modes and its temperature scaling behavior.

Contribution

It demonstrates that the boson peak arises from coupling to transverse acoustic modes and confirms temperature scaling in amorphous silica through simulations.

Findings

Boson peak is due to coupling with transverse acoustic modes.

Dynamic structure factor scales with temperature.

Results align with harmonic approximation predictions.

Abstract

We investigate a prominent vibrational feature in amorphous silica, the so-called boson peak, by means of molecular dynamics computer simulations. The dynamic structure factor S(q,nu) in the liquid, as well as in the glass state, scales roughly with temperature, in agreement with the harmonic approximation. By varying the size of the system and the masses of silicon and oxygen we show that the excitations giving rise to the boson peak are due to the coupling to transverse acoustic modes.