Photoemission Quasi-Particle Spectra of Sr$_2$RuO$_4$

TL;DR

This paper investigates the photoemission spectra of Sr$_2$RuO$_4$ using advanced many-body calculations, revealing anisotropic self-energy effects and charge transfer among bands that influence the material's electronic structure.

Contribution

It introduces a detailed analysis of quasi-particle spectra in Sr$_2$RuO$_4$ considering Coulomb correlations and band-specific distortions, advancing understanding of its electronic properties.

Findings

Highly anisotropic self-energy in photoemission hole states

Charge transfer from narrow to wide bands due to Coulomb correlations

Shift of the $d_{xy}$ van Hove singularity near the Fermi level

Abstract

Multi-band quasi-particle calculations based on perturbation theory and dynamical mean field methods show that the creation of a photoemission hole state in Sr$_2$RuO$_4$ is associated with a highly anisotropic self-energy. Since the narrow Ru-derived $d_{xz,yz}$ bands are more strongly distorted by Coulomb correlations than the wide $d_{xy}$ band, charge is partially transferred from $d_{xz,yz}$ to $d_{xy}$, thereby shifting the $d_{xy}$ van Hove singularity close to the Fermi level.