X-ray absorption branching ratio in actinides: LDA+DMFT approach

TL;DR

This paper develops a theoretical framework combining LDA and DMFT to analyze the X-ray absorption branching ratio in actinides, bridging localized and itinerant electron behaviors, and aligns well with experimental data.

Contribution

It introduces a unified LDA+DMFT approach to study the XAS branching ratio across all actinides, capturing both localized and itinerant electron regimes.

Findings

The method reproduces experimental XAS branching ratios.

It bridges the gap between band and atomic limits.

Provides a comprehensive view of 5f electron behavior.

Abstract

To investigate the x-ray absorption (XAS) branching ratio from the core 4d to valence 5f states, we set up a theoretical framework by using a combination of density functional theory in the local density approximation and Dynamical Mean Field Theory (LDA+DMFT), and apply it to several actinides. The results of the LDA+DMFT reduces to the band limit for itinerant systems and to the atomic limit for localized f electrons, meaning a spectrum of 5f itinerancy can be investigated. Our results provides a consistent and unified view of the XAS branching ratio for all elemental actinides, and is in good overall agreement with experiments.