Empirical relationship between x-ray photoemission spectra and electrical conductivity in a colossal magnetoresistive manganite La_{1-x}Sr_{x}MnO_{3}

TL;DR

This study establishes an empirical semi-quantitative link between x-ray photoemission spectral weight and electrical conductivity in La_{1-x}Sr_{x}MnO_{3}, revealing spectral features associated with different Mn oxidation states and their relation to conductivity.

Contribution

It provides new empirical evidence connecting XPS spectral features with electrical conductivity variations in a manganite material, enhancing understanding of electronic structure-conductivity relationships.

Findings

Spectral weight at Mn 2p_{3/2} HX-PES correlates with conductivity.

Shoulder structure in spectra indicates Mn^{3+} well-screened state.

Near-Fermi level spectral weight reflects conductivity changes despite limited energy resolution.

Abstract

By using laboratory x-ray photoemission spectroscopy (XPS) and hard x-ray photoemission spectroscopy (HX-PES) at a synchrotron facility, we report an empirical semi-quantitative relationship between the valence/core-level x-ray photoemission spectral weight and electrical conductivity in La_{1-x}Sr_{x}MnO_{3} as a function of x. In the Mn 2p_{3/2} HX-PES spectra, we observed the shoulder structure due to the Mn^{3+} well-screened state. However, the intensity at x=0.8 was too small to explain its higher electrical conductivity than x=0.0, which confirms our recent analysis on the Mn 2p_{3/2} XPS spectra. The near-Fermi level XPS spectral weight was found to be a measure of the variation of electrical conductivity with x in spite of a far lower energy resolution compared with the energy scale of the quasiparticle (coherent) peak because of the concurrent change of the coherent and incoherent spectral weight.