High Frequency dynamics in metallic glasses

TL;DR

This study investigates the collective dynamics of a metallic glass using Inelastic X-ray Scattering, revealing well-defined acoustic-like excitations above the Boson Peak energy, thus providing new insights into high-frequency behaviors in metallic glasses.

Contribution

It presents the first exploration of the energy-momentum region in metallic glasses, demonstrating the existence of acoustic-like excitations above the Boson Peak energy.

Findings

Identification of momentum transfer dependence of sound velocity.

Observation of acoustic damping behavior.

Existence of well-defined acoustic-like excitations above the Boson Peak.

Abstract

Using Inelastic X-ray Scattering we studied the collective dynamics of the glassy alloy Ni$_{33}$Zr$_{67}$ in the first pseudo Brillouin zone, an energy-momentum region still unexplored in metallic glasses. We determine key properties such as the momentum transfer dependence of the sound velocity and of the acoustic damping, discussing the results in the general context of recently proposed pictures for acoustic dynamics in glasses. Specifically, we demonstrate the existence in this strong glass of well defined (in the Ioffe Regel sense) acoustic-like excitations well above the Boson Peak energy.