Inelastic x-ray scattering measurements on URu2Si2

TL;DR

This study uses high-resolution inelastic x-ray scattering to investigate phonon behavior in URu2Si2, finding minimal changes across the Hidden Order phase and suggesting magnetic excitations influence thermal conductivity.

Contribution

It provides detailed phonon measurements in URu2Si2 and challenges the idea that phonon changes drive thermal conductivity increases in the Hidden Order phase.

Findings

Phonon structure remains largely unchanged across the Hidden Order transition.

Longitudinal acoustic phonons are anomalously broad at low q at all temperatures.

Magnetic excitations likely contribute to thermal transport, not phonon modifications.

Abstract

We report high-resolution inelastic x ray scattering measurements of the acoustic phonons of URu2Si2. We observe minimal change in the phonon structure upon entering the Hidden Order phase. At all temperatures, the longitudinal acoustic phonons are anomalously broad at low q. There is no evidence to suggest that the increase in thermal conductivity in the Hidden Order phase is driven by a change in phonon dispersions or lifetimes. A more likely explanation is that the magnetic excitations in the Hidden Order state contribute to thermal transport.