Auger Effect in the High-Resolution Ce 3d-edge Resonant Photoemission

TL;DR

This study investigates the Auger effect in Ce 3d-edge resonant photoemission, revealing how small photon energy changes significantly affect spectral lineshapes due to multiplet state transitions, impacting spectral weight extraction.

Contribution

It demonstrates that the Auger transition influences spectral lineshapes in Ce 3d-edge resonant photoemission, emphasizing the importance of photon energy selection for accurate spectral analysis.

Findings

Lineshapes vary with small photon energy changes.

Auger transitions between multiplet states dominate spectral features.

Choosing the lowest multiplet energy is optimal for spectral weight extraction.

Abstract

The bulk-sensitive Ce 4$f$ spectral weights of various Ce compounds including CeFe$_2$, CeNi$_2$, and CeSi$_2$ were obtained with the resonant photoemission technique at the Ce 3d-edge. We found the lineshapes change significantly with the small change of the incident photon energy. Detailed analysis showed that this phenomenon results primarily from the Auger transition between different multiplet states of the Ce $\underline{3d_{5/2}}4f^2$ (bar denotes a hole) electronic configuration in the intermediate state of the resonant process. This tells us that extra care should be taken for the choice of the resonant photon energy when extracting Ce 4$f$ spectral weights from the Ce 3$d$-edge resonant photoemission spectra. The absorption energy corresponding to the lowest multiplet structure of the Ce $\underline{3d_{5/2}}4f^2$ configuration seems to be the logical choice.