# Ce 3$p$ hard x-ray photoelectron spectroscopy study of the topological Kondo insulator CeRu$_4$Sn$_6$

## TL;DR

This study uses hard x-ray photoelectron spectroscopy to analyze the Ce 3$p$ core level in CeRu$_4$Sn$_6$, revealing it as a moderately mixed valence Kondo insulator with detailed spectral analysis.

## Contribution

It provides a detailed lineshape analysis of Ce 3$p$ spectra using a combined multiplet and configuration model, accounting for plasmon correlations.

## Key findings

- CeRu$_4$Sn$_6$ is a moderately mixed valence compound.
- The Ce $f^0$ configuration contributes 8% to the ground state.
- Spectral analysis accurately captures plasmon effects.

## Abstract

Bulk sensitive hard x-ray photoelectron spectroscopy data of the Ce 3$p$ core level of CeRu$_4$Sn$_6$ are presented. Using a combination of full multiplet and configuration iteration model we were able to obtain an accurate lineshape analysis of the data, thereby taking into account correlations for the strong plasmon intensities. We conclude that CeRu$_4$Sn$_6$ is a moderately mixed valence compound with a weight of 8% for the Ce $f^0$ configuration in the ground state.