Resonant Inelastic X-ray Scattering Studies of Elementary Excitations

TL;DR

Resonant Inelastic X-ray Scattering (RIXS) has advanced significantly over the past decade, enabling detailed studies of elementary excitations in complex materials through high-brilliance sources and sophisticated analysis.

Contribution

This review summarizes recent experimental and theoretical developments in RIXS, highlighting its capabilities and future potential in probing elementary excitations in correlated electron systems.

Findings

RIXS effectively probes charge, spin, orbital, and lattice excitations.

Recent experimental data have enhanced understanding of correlated electron systems.

Theoretical methods for computing RIXS responses have advanced significantly.

Abstract

In the past decade, Resonant Inelastic X-ray Scattering (RIXS) has made remarkable progress as a spectroscopic technique. This is a direct result of the availability of high-brilliance synchrotron X-ray radiation sources and of advanced photon detection instrumentation. The technique's unique capability to probe elementary excitations in complex materials by measuring their energy-, momentum-, and polarization-dependence has brought RIXS to the forefront of experimental photon science. We review both the experimental and theoretical RIXS investigations of the past decade, focusing on those determining the low-energy charge, spin, orbital and lattice excitations of solids. We present the fundamentals of RIXS as an experimental method and then review the theoretical state of affairs, its recent developments and discuss the different (approximate) methods to compute the dynamical RIXS response. The last decade's body of experimental RIXS data and its interpretation is surveyed, with an emphasis on RIXS studies of correlated electron systems, especially transition metal compounds. Finally, we discuss the promise that RIXS holds for the near future, particularly in view of the advent of x-ray laser photon sources.