Resonant X-Ray Scattering from URu_{2}Si_{2}

TL;DR

This paper analyzes resonant x-ray scattering spectra in URu_{2}Si_{2} using a crystal electric field model, aiming to distinguish between antiferroquadrupolar and antiferromagnetic phases through spectral shape differences.

Contribution

It provides a detailed theoretical analysis of x-ray spectra considering different order parameters and level schemes, aiding phase identification in URu_{2}Si_{2}.

Findings

Spectral shapes are independent of the level scheme.

Spectral differences distinguish between quadrupolar and magnetic phases.

Analysis can help determine the nature of the ordered phase.

Abstract

Based on a localized crystal electric field model for the U^{4+} in the (5f)^2-configuration, we analyze the resonant x-ray scattering spectra around U M_{IV} and M_{V} edges in URu_{2}Si_{2}, taking full Coulomb and spin-orbit interactions into account. We consider two level schemes, a singlet model of Santini and Amoretti and a doublet model of Ohkawa and Shimizu, and assume the antiferroquadrupolar order and the antiferromagnetic order as candidates for the ambient pressure phase and the high pressure phase. It is found that the spectral shapes as a function of photon energy are independent of the assumed level scheme, but are quite different between the antiferroquadrupole and antiferromagnetic phases, This may be useful to determine the character of the ordered phase.