X-ray Raman scattering with Bragg diffraction in a La-based superlattice

TL;DR

This study investigates X-ray Raman scattering in a La-based superlattice, revealing how Bragg diffraction influences the scattered intensity and energy shifts, supported by a model based on energy and momentum conservation.

Contribution

It demonstrates the occurrence of Bragg-assisted Raman scattering in a La multilayer and provides a simple theoretical model to explain the observed energy shifts.

Findings

Observed a shifted scattered intensity peak with changing scattering angles.

Identified the peak as Raman scattering assisted by Bragg diffraction.

Developed a model explaining the energy variation of the peak.

Abstract

The non-dispersed soft x-ray emission from a La/B4C periodic multilayer irradiated by monochromatic x-rays has been measured as a function of the incident photon energy in the 125-200 eV range for different scattering angles. We have observed a scattered intensity peak at incident energies which shift towards the low-energy side as the value of the scattering angle increases. These observations are interpreted as Raman scattering by the 5p level of lanthanum assisted by Bragg diffraction from the lattice of the periodic multilayer. A simple model based upon the laws of energy and momentum conservation enables us to account for the variation of the incident energy associated with the Bragg-Raman peak.