GW correlation effects on plutonium quasiparticle energies: changes in crystal-field splitting

TL;DR

This study uses a quasiparticle self-consistent GW method to analyze how electronic correlations affect plutonium's quasiparticle energies and crystal-field splitting across different volumes, revealing significant band narrowing effects.

Contribution

It applies a novel self-consistent GW approach to plutonium, highlighting how correlations influence quasiparticle energies and crystal-field splitting as a function of volume.

Findings

Correlation narrows f bands in two ways: flatter dispersion and reduced crystal-field splitting.

Self-consistent GW results differ from LDA, showing systematic trends in electronic structure.

Significant effects observed as a function of volume and f orbital localization.

Abstract

We present results for the electronic structure of plutonium by using a recently developed quasiparticle self-consistent $GW$ method (\qsgw). We consider a paramagnetic solution without spin-orbit interaction as a function of volume for the face-centered cubic (fcc) unit cell. We span unit-cell volumes ranging from 10% greater than the equilibrium volume of the $\delta$ phase to 90 % of the equivalent for the $\alpha$ phase of Pu. The self-consistent $GW$ quasiparticle energies are compared to those obtained within the Local Density Approximation (LDA). The goal of the calculations is to understand systematic trends in the effects of electronic correlations on the quasiparticle energy bands of Pu as a function of the localization of the $f$ orbitals. We show that correlation effects narrow the $f$ bands in two significantly different ways. Besides the expected narrowing of individual $f$ bands (flatter dispersion), we find that an even more significant effect on the $f$ bands is a decrease in the crystal-field splitting of the different bands.