Origin of f-orbital-bonding insensitivity to spin-orbit coupling in UO₂

¹ Department of Chemistry, Pohang University of Science and Technology - Pohang 790-784, Korea
² Division of Advanced Nuclear Engineering, Pohang University of Science and Technology - Pohang 790-784, Korea
³ Department of Mechanical Engineering, University of Michigan - Ann Arbor, MI 48109, USA
⁴ Department of Physics, Pohang University of Science and Technology - Pohang 790-784, Korea

^(a) jhshim@postech.ac.kr

Received: 17 August 2015
Accepted: 4 October 2015

Abstract

The origin of negligible spin-orbit coupling effects on the ground-state properties of UO₂ is examined using the LDA+DMFT and the LSDA+U methods. Although the previous theoretical results neglecting the spin-orbit coupling (SOC) are in reasonable agreement with experiments, this insensitivity has not been investigated. Via the charge density distribution, we show that the SOC does not affect the U-O bonding states which are directly related to the bonding properties (e.g., lattice constant, bulk modulus, and oxidation/reduction energies).