Measuring velocity of sound with nuclear resonant inelastic x-ray scattering

TL;DR

This paper introduces a method using nuclear resonant inelastic x-ray scattering to measure sound velocity by relating phonon density of states to low-energy vibrational dynamics, applicable to various materials.

Contribution

The authors derive a new relationship between phonon density of states and sound velocity, expanding measurement techniques for diverse materials using nuclear resonant inelastic x-ray scattering.

Findings

Method successfully applied to different material types

Provides a new way to estimate sound velocity from phonon data

Highlights advantages and limitations of the approach

Abstract

Nuclear resonant inelastic x-ray scattering is used to measure the projected partial phonon density of states of materials. A relationship is derived between the low-energy part of this frequency distribution function and the sound velocity of materials. Our derivation is valid for harmonic solids with Debye-like low-frequency dynamics. This method of sound velocity determination is applied to elemental, composite, and impurity samples which are representative of a wide variety of both crystalline and noncrystalline materials. Advantages and limitations of this method are elucidated.