Observation and theoretical description of the pure Fano-effect in the valence-band photo-emission of ferromagnets

TL;DR

This paper reports the first observation of the pure Fano-effect in valence-band photo-emission of ferromagnets, supported by theoretical analysis that aligns well with experimental data, especially when advanced correlation effects are included.

Contribution

It provides the first experimental observation of the pure Fano-effect in ferromagnets and offers a theoretical framework that explains the spectra with improved accuracy using DMFT.

Findings

First observation of pure Fano-effect in ferromagnets

Good quantitative agreement for Fe and Co spectra

Qualitative agreement for Ni improved by DMFT

Abstract

The pure Fano-effect in angle-integrated valence-band photo-emission of ferromagnets has been observed for the first time. A contribution of the intrinsic spin polarization to the spin polarization of the photo-electrons has been avoided by an appropriate choice of the experimental parameters. The theoretical description of the resulting spectra reveals a complete analogy to the Fano-effect observed before for paramagnetic transition metals. While the theoretical photo-current and spin difference spectra are found in good quantitative agreement with experiment in the case of Fe and Co only a qualitative agreement could be achieved in the case of Ni by calculations on the basis of plain local spin density approximation (LSDA). Agreement with experimental data could be improved in this case in a very substantial way by a treatment of correlation effects on the basis of dynamical mean field theory (DMFT).