Incident-energy-dependent spectral weight of resonant inelastic x-ray scattering in doped cuprates

TL;DR

This paper theoretically examines how incident photon energy influences RIXS spectral weight in doped cuprates, revealing dependence on core-hole interactions and doping type, aligning with experimental observations.

Contribution

It introduces a detailed theoretical analysis of incident-energy dependence in RIXS for cuprates, highlighting the role of core-hole Coulomb interactions and doping effects.

Findings

RIXS shows fluorescencelike or Raman-like behavior depending on core-hole interactions.

Core-hole Coulomb interaction is larger than on-site Coulomb, explaining experimental results.

Predicted spectral shifts in electron-doped systems with small spectral weight.

Abstract

We theoretically investigate the incident-photon energy omega_i dependence of resonant inelastic x-ray scattering (RIXS) tuned for the Cu L edge in cuprate superconductors by using the exact diagonalization technique for a single-band Hubbard model. Depending on the value of core-hole Coulomb interaction in the intermediate state, RIXS for non-spin-flip channel shows either a omega_i-dependent fluorescencelike or omega_i-independent Raman-like behavior for hole doping. An analysis of x-ray absorption suggests that the core-hole Coulomb interaction is larger than on-site Coulomb interaction in the Hubbard model, resulting in a fluorescencelike behavior in RIXS consistent with recent RIXS experiments. A shift on the high-energy side of the center of spectral distribution is also predicted for electron-doped systems though spectral weight is small. Main structures in spin-flip channel exhibit a Raman-like behavior as expected, accompanied with a fluorescencelike behavior with small intensity.