Spin and Orbital Characters of Excitations in Iron Arsenide Superconductors Revealed by Simulated Fe L-Edge RIXS

TL;DR

This paper uses theoretical calculations to analyze the orbital and spin excitations in iron-arsenide superconductors, providing detailed predictions for Fe L-edge RIXS spectra and their polarization and momentum dependence.

Contribution

It offers a comprehensive theoretical analysis of orbital and spin excitations in iron-arsenide superconductors using a five-band model, predicting RIXS spectral features and their experimental signatures.

Findings

Magnon excitations mainly from a single orbital component

Presence of spin-flip interorbital high-energy excitations

Predicted polarization and momentum dependence of RIXS spectra

Abstract

We theoretically examine the orbital excitations coupled to the spin degree of freedom in the parent state of the iron-arsenide superconductor, based on the calculation in a five-band itinerant model. The calculated Fe $L_3$-edge resonant inelastic x-ray scattering (RIXS) spectra disclose the presence of spin-flip excitations involving several specific orbitals. Magnon excitations predominantly composed of a single orbital component can be seen in experiments, although its spectral weight is smaller than spin-flipped interorbital high-energy excitations. The detailed polarization and momentum dependence is also discussed with predictions for the experiments.