q-Dependence of the giant bond-stretching phonon anomaly in the stripe compound La1.48Nd0.4Sr0.12CuO4 measured by IXS

TL;DR

This study uses high-resolution inelastic x-ray scattering to analyze the bond-stretching phonon anomaly in La1.48Nd0.4Sr0.12CuO4, revealing details about its width and shape, and comparing it with neutron scattering results.

Contribution

It provides a detailed characterization of the phonon anomaly's width and shape, clarifying previous neutron scattering observations with IXS data.

Findings

The intrinsic width of the phonon anomaly is approximately 0.08 r.l.u.

The two-peak lineshape observed in neutron scattering is mainly an artifact of poor resolution.

High-resolution IXS confirms the agreement with neutron scattering after accounting for resolution effects.

Abstract

Inelastic x-ray scattering (IXS) was used to study the Cu-O bond-stretching vibrations in the static stripe phase compound La1.48Nd0.4Sr0.12CuO4. It was found that the intrinsic width in Q-space of the previously reported huge anomalous phonon softening and broadening is approximately 0.08r.l.u HWHM. A detailed comparison was also made to inelastic neutron scattering (INS) studies, which indicate a two-peak lineshape (with superimposed broad and narrow peaks) in the vicinity of the anomaly. The high resolution IXS data show that the narrow peak is mostly an artifact of the poor transverse Q-resolution of INS. Otherwise the agreement between the INS and IXS was excellent.