Bulk screening in core level photoemission from Mott-Hubbard and Charge-Transfer systems

TL;DR

This study uses bulk-sensitive hard X-ray photoemission to investigate electronic structures in Mott-Hubbard and charge-transfer systems, revealing temperature-dependent satellite features and validating models with experimental data.

Contribution

It provides new insights into bulk electronic states in correlated materials using high-energy photoemission and advanced cluster model calculations.

Findings

V$_{1.98}$Cr$_{0.02}$O$_{3}$ shows temperature-dependent satellite suppression.

Bi2212's Cu $2p$ spectra lack temperature dependence but show increased bulk satellite weight.

Cluster model calculations agree well with experimental spectra.

Abstract

We report bulk-sensitive hard X-ray ($h\nu$ = 5.95 KeV) core level photoemission spectroscopy (PES) of single crystal V$_{1.98}$Cr$_{0.02}$O$_{3}$ and the high-$T_c$ cuprate Bi$_2$Sr$_{2}$CaCu$_{2}$O$_{8+\delta}$ (Bi2212). V$_{1.98}$Cr$_{0.02}$O$_{3}$ exhibits low binding energy "satellites" to the V $2p$ "main lines" in the metallic phase, which are suppressed in the antiferromagnetic insulator phase. In contrast, the Cu $2p$ spectra of Bi2212 do not show temperature dependent features, but a comparison with soft X-ray PES indicates a large increase in the $2p^5 3d^9$ "satellites" or $3d^9$ weight in the bulk. Cluster model calculations, including full multiplet structure and a screening channel derived from the coherent band at the Fermi energy, give very satisfactory agreement with experiments.