Resonant inelastic x-ray scattering study of the electronic structure of Cu$_2$O

TL;DR

This study uses resonant inelastic x-ray scattering to investigate the electronic structure of Cu₂O, revealing interband transitions, the band gap, and momentum-dependent features consistent with photoemission data.

Contribution

It provides detailed insights into Cu₂O's electronic structure using RIXS, including band gap measurement and valence-conduction band transition characterization.

Findings

Enhanced spectral features at Cu K-edge indicate interband transitions.

Observed band gap aligns with previous photoemission results.

Momentum dependence of the lower bound matches ARPES data.

Abstract

A resonant inelastic x-ray scattering study of the electronic structure of the semiconductor cuprous oxide, $\rm Cu_2O$, is reported. When the incident x-ray energy is tuned to the Cu K-absorption edge, large enhancements of the spectral features corresponding to the electronic transitions between the valence band and the conduction band are observed. A feature at 6.5 eV can be well described by an interband transition from occupied states of mostly Cu 3d charactor to unoccupied states with mixed 3d, 4s and 2p character. In addition, an insulating band gap is observed, and the momentum dependence of the lower bound is measured along the $\Gamma-R$ direction. This is found to be in good agreement with the valence band dispersion measured with angle-resolved photoemission spectroscopy.