Comparative analysis of models for theα−γphase transition in cerium: A DFT+DMFT study using Wannier orbitals

Abstract

We clarify the orbital mechanism of the $\ensuremath{\alpha}\text{\ensuremath{-}}\ensuremath{\gamma}$ transition in cerium. First we built an $sdf$ Wannier orbital basis to describe the electronic structure of cerium. Second, we use this basis to study the relative role of several orbital hoppings upon compression of cerium. Third, we use DFT + DMFT calculations to quantify the impact of these hoppings on electronic structure. Our conclusion is that upon compression of $\ensuremath{\gamma}$ cerium, the change of hybridization is due to both interatomic $ff$ and $fd$ hopping integrals. In particular, neglecting $ff$ hoppings leads to an important renormalization of both the hybridization and the quasiparticle peak. Thus, neither the Kondo volume collapse nor the Mott transition model are sufficient to describe the isostructural transition in cerium.