Quasiparticle multiplets and 5f electronic correlation in prototypical plutonium borides

TL;DR

This study investigates the complex 5f electron behavior in plutonium borides using advanced theoretical methods, revealing quasiparticle multiplets, mixed-valence states, and orbital-dependent correlations that influence their electronic properties.

Contribution

It combines density functional theory and dynamical mean-field theory to elucidate the dual localized-itinerant nature and orbital correlations of Pu-5f electrons in various plutonium borides, providing new insights into their electronic structures.

Findings

Reproduced the topological insulator phase in PuB6.

Predicted metallicity in PuBx compounds.

Identified moderate and orbital-selective 5f correlations.

Abstract

To elucidate the localized-itinerant dual nature and orbital dependent correlations of Pu-5f valence electrons in plutonium borides (PuBx, x=1, 2, 6, 12), the electronic structures are throughout investigated by using the combination of density functional theory and single-site dynamical mean-field method. We not only reproduce the correlated topological insulator of PuB6, but also predict the metallicity in PuBx (x=1, 2, 12). It is found that the momentum-resolved spectral functions, density of states, hybridization functions all indicate partially itinerant 5f states in PuBx (x=1, 2, 6, 12). Especially, quasiparticle multiplets induced noteworthy valence state fluctuations implying the mixed-valence behavior of plutonium borides. Moreover, the itinerant degree of freedom for 5f electrons in PuBx (x=1, 2, 12) is tuned by hybridization strength between 5f states and conduction bands, which is affected by atomic distance between Pu and B atoms. Lastly, 5f electronic correlations encoded in the electron self-energy functions demonstrate moderate 5f electronic correlations in PuB6 and orbital selective 5f electronic correlations in PuBx (x=1, 2, 12). Consequently, the understanding of electronic structure and related crystal structure stability shall shed light on exploring novel 5f electrons states and ongoing experiment research.