Comment on: Quantitative study of the $f$ occupation in CeMIn5 and other cerium compounds with hard X-rays, [arXiv:1601.03270]

TL;DR

This comment clarifies the ambiguity in defining cerium valence in X-ray studies, emphasizing the importance of distinguishing hybridized and localized 4-f states for understanding strong correlations in cerium compounds.

Contribution

It highlights the need to differentiate hybridized and localized 4-f states in cerium compounds for accurate interpretation of valence and correlation effects.

Findings

Hybridized 4-f states are mixed with localized states in models.

Differentiating hybridized and localized states is crucial for understanding correlations.

Clarifies the definition of cerium valence in spectroscopic studies.

Abstract

This comment clarifies the mixed definition of the cerium valence in the article entitled: Quantitative study of the $f$ occupation in CeMIn5 and other cerium compounds with hard X-rays, published in Journal of Electron Spectroscopy and Related Phenomena http://www.sciencedirect.com/science/article/pii/S0368204816300123 and available on arXiv:1601.03270. Indeed, it is unclear wether electrons belonging on hybridized f-states are part or not of the valence. When one tries to simulate the system, an Anderson impurity model only includes valence bands electrons and localized 4-f states. Therefore hybridized 4-f states are mixed with the localized ones. From a heavy fermion perspective it however essential to differentiate hybridized and localized states as only the second are responsible for strong correlations, such as obtained by susceptibility or direct comparisons to model systems.