Observation of High-frequency Transverse Phonons in Metallic Glasses

TL;DR

This study demonstrates that high-frequency transverse phonons exist in metallic glasses and are correlated with the static structure, revealing their importance in understanding disordered materials.

Contribution

It provides experimental and simulation evidence of persistent high-frequency transverse phonons in metallic glasses and establishes a universal correlation with structural features.

Findings

Transverse phonons persist into high-frequency regimes.

Peak width of transverse phonons correlates with static structure factor.

Universal correlation between phonon dynamics and structure in disordered materials.

Abstract

Using inelastic neutron scattering and molecular dynamics simulations on a model Zr-Cu-Al metallic glass, we show that transverse phonons persist well into the high-frequency regime, and can be detected at large momentum transfer. Furthermore, the apparent peak width of the transverse phonons was found to follow the static structure factor. The one-to-one correspondence, which was demonstrated for both Zr-Cu-Al metallic glass and a 3-dimensional Lennard-Jones model glass, suggests a universal correlation between the phonon dynamics and the underlying disordered structure. This remarkable correlation, not found for longitudinal phonons, underscores the key role that transverse phonons hold for understanding the structure-dynamics relationship in disordered materials.