TITLE:
Key Role of Hybridization between Actinide 5f and Oxygen 2p Orbitals for Electronic Structure of Actinide Dioxides
AUTHORS:
Yu Hasegawa, Takahiro Maehira, Takashi Hotta
KEYWORDS:
Tight-Binding Approximation; Actinide Dioxides; f-p Hybridization; Crystalline Electric Field Potential
JOURNAL NAME:
Journal of Modern Physics,
Vol.4 No.12,
December
11,
2013
ABSTRACT:
In order to promote our understanding on electronic structure of actinide dioxides, we construct a tight-binding model composed of actinide 5f and oxygen 2p electrons, which is called f-p model. After the diagonalization of the f-p model, we compare the eigen-energies in the first Brillouin zone with the results of relativistic band-structure calculations. Here we emphasize a key role of f-p hybridization in order to understand the electronic structure of actinide dioxides. In particular, it is found that the position of energy levels of Г7 and Г8 states determined from crystalline electric field (CEF) potentials depends on the f-p hybridization. We investiagte the values of the Slater-Koster integrals for f-p hybridization, (fpσ) and (fpπ), which reproduce simultaneously the local CEF states and the band-structure calculation results. Then, we find that the absolute value of (fpπ) should be small in comparison with (fpσ) = 1 eV. The small value of |(fpπ)| is consistent with the condition to obtain the octupole ordering in the previous analysis of the f-p model.