Quantitative determination of spin-dependent quasiparticle lifetimes and electronic correlations in hcp cobalt

TL;DR

This study combines spin-resolved photoemission experiments with advanced many-body calculations to analyze spin-dependent quasiparticle lifetimes and electron correlations in ferromagnetic hcp cobalt, highlighting the need for more refined models for quantitative accuracy.

Contribution

It provides a detailed comparison of experimental spectra with state-of-the-art many-body theories, emphasizing the importance of non-local correlations in cobalt.

Findings

Strong local Coulomb interactions are crucial for qualitative understanding.

Current models still lack quantitative accuracy in linewidth predictions.

Non-local correlations appear less significant with increasing atomic number.

Abstract

We report on a quantitative investigation of the spin-dependent quasiparticle lifetimes and electron correlation effects in ferromagnetic hcp Co(0001) by means of spin and angle-resolved photoemission spectroscopy. The experimental spectra are compared in detail to state-of-the-art many-body calculations within the dynamical mean field theory and the three-body scattering approximation, including a full calculation of the one-step photoemission process. From this comparison we conclude that although strong local many-body Coulomb interactions are of major importance for the qualitative description of correlation effects in Co, more sophisticated many-body calculations are needed in order to improve the quantitative agreement between theory and experiment, in particular concerning the linewidths. The quality of the overall agreement obtained for Co indicates that the effect of non-local correlations becomes weaker with increasing atomic number.