Pressure-Driven 5$f$ Localized-Itinerant Transition and Valence Fluctuation in Californium

TL;DR

This study uses advanced computational methods to explore how pressure influences the electronic structure of californium, revealing a transition from localized to itinerant 5f electrons and associated valence fluctuations.

Contribution

It demonstrates the pressure-induced orbital-selective transition and valence fluctuation in californium using combined density functional and dynamical mean-field theories.

Findings

Pressure causes 5f electrons to transition from localized to itinerant states.

Volume contraction leads to charge redistribution and valence fluctuations.

Angular momentum coupling remains unaffected by pressure.

Abstract

A combination of the density functional theory and the single-site dynamical mean-field theory is employed to study the pressure dependence of electronic structure for cubic phase californium. We predict that its 5$f$ electrons could undergo an orbital-selective localized-itinerant transition under moderate pressure. The volume contraction causes remarkable charge redistribution and valence fluctuation behaviors, which are the driving forces of the divalent-trivalent transition. Additionally, we find that the angular momentum coupling mechanism is hardly affected by pressure. The 5$f$ orbital occupancy is well described by the intermediate coupling scheme.