Resonant inelastic x-ray scattering in electronically quasi-zero-dimensional CuB2O4

TL;DR

This paper investigates the RIXS process in CuB2O4, revealing the importance of intermediate-state effects and providing a simplified model that explains the observed d-d excitations and interference phenomena.

Contribution

It introduces a new calculation method that accounts for intermediate-state effects in RIXS, enhancing understanding of the scattering phenomenology in quasi-zero-dimensional cuprates.

Findings

Intermediate-state effects are significant in RIXS spectra.

A simplified model accurately reproduces experimental features.

Interference effects influence the interpretation of d-d excitations.

Abstract

We explore the general phenomenology of resonant inelastic scattering (RIXS) using CuB2O4, a network of CuO4 plaquettes electronically isolated by B+3 ions. Spectra show a small number of well-separated features, and we exploit the simple electronic structure to explore RIXS phenomenology by developing a calculation which allows for intermediate-state effects ignored in standard approaches. These effects are found to be non-negligible and good correspondence between our model and experiment leads to a simple picture of such phenomenology as the genesis of d-d excitations at the K edge and intermediate-state interference effects.