Spectral Properties of delta-Plutonium: Sensitivity to 5f Occupancy

TL;DR

This study combines advanced computational methods to analyze how the spectral properties of delta-plutonium depend on 5f electron occupancy, revealing high sensitivity and identifying the most accurate electronic configuration.

Contribution

It introduces a systematic analysis of delta-plutonium's spectral properties using LDA+DMFT with variable 5f occupancy, highlighting the importance of occupancy as a fitting parameter.

Findings

Spectral properties are highly sensitive to 5f occupancy.

Open shell 5f^5 configuration best matches PES data.

The study resolves the debate over 5f shell configurations in delta-Pu.

Abstract

By combining the local density approximation (LDA) with dynamical mean field theory (DMFT), we report a systematic analysis of the spectral properties of $\delta$-plutonium with varying $5f$ occupancy. The LDA Hamiltonian is extracted from a tight-binding (TB) fit to full-potential linearized augmented plane-wave (FP-LAPW) calculations. The DMFT equations are solved by the exact quantum Monte Carlo (QMC) method and the Hubbard-I approximation. We have shown for the first time the strong sensitivity of the spectral properties to the $5f$ occupancy, which suggests using this occupancy as a fitting parameter in addition to the Hubbard $U$. By comparing with PES data, we conclude that the ``open shell'' $5f^{5}$ configuration gives the best agreement, resolving the controversy over $5f$ ``open shell'' versus ``close shell'' atomic configurations in $\delta$-Pu.