Ab initio investigation on oxygen defect clusters in UO2+x

Abstract

By first-principles LSDA+U calculations, we revealed that the current physical picture of defective uranium dioxide suggested solely by neutron diffraction analysis is unsatisfactory. An understanding based on quantum theory has been established as a thermodynamical competition among point defects and cuboctahedral cluster, which naturally interprets the puzzled origin of the asymmetric O' and O'' interstitials. It also gives a clear and consistent agreement with most available experimental data. Unfortunately, the observed high occupation of O'' site cannot be accounted for in this picture and is still a challenge for theoretical simulations.

4 pages, 3 figures, title changed

References in corpus (3)

• Point defects and clustering in uranium dioxide by LSDA+U calculations
• Structural behavior of uranium dioxide under pressure by LSDA+U calculations
• Stability mechanism of cuboctahedral clusters in UO2: First-principles calculations

Cited by in corpus (5)

• Interplay of defect cluster and the stability of xenon in uranium dioxide by density functional calculations
• Ab initio DFT+U study of He atom incorporation into UO2 crystals
• First-principles study on oxidation effects in uranium oxides and high-pressure high-temperature behavior of point defects in uranium dioxide
• Anomalies in non-stoichiometric uranium dioxide induced by pseudo-phase transition of point defects
• Theoretical assessment on the possibility of constraining point defect energetics by pseudo-phase transition pressures