X-ray spectrum of a pinned charge density wave

TL;DR

This paper calculates the X-ray diffraction spectrum of a pinned charge density wave, revealing asymmetric satellite peaks indicative of a Bragg glass phase and discussing experimental detection methods.

Contribution

It provides a theoretical prediction of the X-ray diffraction signature of a Bragg glass phase in pinned charge density waves, including effects of Coulomb interactions.

Findings

Asymmetric satellite peaks indicate Bragg glass phase

Peak divergence and anisotropy are enhanced by Coulomb interactions

Finite resolution affects experimental detection of the phase

Abstract

We calculate the X-ray diffraction spectrum produced by a pinned charge density wave (CDW). The signature of the presence of a CDW consists of two satellite peaks, asymmetric as a consequence of disorder. The shape and the intensity of these peaks are determined in the case of a collective weak pinning using the variational method. We predict divergent asymmetric peaks, revealing the presence of a Bragg glass phase. We deal also with the long range Coulomb interactions, concluding that both peak divergence and anisotropy are enhanced. Finally we discuss how to detect experimentally the Bragg glass phase in the view of the role played by the finite resolution of measurements.