Revisiting the origin of satellites in core level photoemission of transparent conducting oxides: the case of $n$-doped SnO$_2$

TL;DR

This paper investigates the origin of satellite features in core level photoemission spectra of n-doped SnO₂, revealing that coupling to plasma oscillations explains these satellites and emphasizing the need for advanced models beyond simple electron gas approximations.

Contribution

It provides ab initio calculations linking satellite structures in photoemission spectra to plasma oscillations in doped SnO₂, advancing understanding of electron correlation effects in narrow-band materials.

Findings

Strong satellites arise from coupling to plasma oscillations.

Spectral changes are related to dynamical screening effects.

Going beyond simple models is necessary for accurate interpretation.

Abstract

The longstanding problem of interpretation of satellite structures in core level photoemission spectra of metallic systems with a low density of conduction electrons is addressed using the specific example of Sb-doped SnO$_2$. Comparison of {\it ab initio} many-body calculations with experimental hard X-ray photoemission spectra of the Sn 4$d$ states shows that strong satellites are produced by coupling of the Sn core hole to the plasma oscillations of the free electrons introduced by doping. Within the same theoretical framework, spectral changes of the valence band spectra are also related to dynamical screening effects. These results demonstrate that, for the interpretation of electron correlation features in the core level photoelectron spectra of such narrow-band materials, going beyond the homogeneous electron gas electron-plasmon coupling model is essential.