Core-Level X-Ray Photoemission Satellites in Ruthenates: A New Mechanism Revealing the Mott Transition

TL;DR

This study investigates core-level X-ray photoemission spectra of ruthenates, revealing a new mechanism that links spectral features to the Mott transition, with implications for understanding strongly correlated electron systems.

Contribution

The paper introduces a novel interpretation of photoemission satellites as a tool to identify Mott transitions in strongly correlated materials.

Findings

Screened peaks appear in metallic ruthenates but are absent in Mott insulators.

The spectral behavior is explained by dynamical mean-field theory calculations.

The mechanism can be applied to nano-scale devices and phase-separated systems.

Abstract

Ru 3d core-level x-ray photoemission spectra of various ruthenates are examined. They show in general two-peak structures, which can be assigned as the screened and unscreened peaks. The screened peak is absent in a Mott insulator, but develops into a main peak in the metallic regime. This spectral behavior is well explained by the dynamical mean-field theory calculation for the single-band Hubbard model with on-site core-hole potential using the exact diagonalization method. The new mechanism of the core-level photoemission satellite can be utilized to reveal the Mott transition phenomenon in various strongly correlated electron systems, especially in nano-scale devices and phase-separated materials.