2007/02/22 by Hua-Yun Geng, H. Y. Geng, Y. Chen +3 · 4 citations
Chemistry · Earth and Planetary Sciences · Materials Science · Physics and Astronomy · #High-pressure geophysics and materials #Nuclear Materials and Properties #Radioactive element chemistry and processing #cond-mat.mtrl-sci #cond-mat.str-el #physics.comp-ph
paper · pdf · doi:10.1103/physrevb.75.054111
published as PHYSICAL REVIEW B 75, 054111 (2007) · 10 pages, 8 figures
openalex publication_date 2007/02/22 · arxiv created 2007/03/26 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
The structural behavior of UO2 under high pressure up to 300\phantom\rule0.3em0exGPa has been studied by first-principles calculations with LSDA+U approximation. The results show that a pressure-induced structural transition to the cotunnite-type (orthorhombic Pnma) phase occurs at 38\phantom\rule0.3em0exGPa. It agrees well with the experimentally observed \ensuremath∼42\phantom\rule0.3em0exGPa. An isostructural transition following that is also predicted to take place from 80\phantom\rule0.3em0exto\phantom\rule0.3em0ex130\phantom\rule0.3em0exGPa, which has not yet been observed in experiments. Further high compression beyond 226\phantom\rule0.3em0exGPa will result in a metallic and paramagnetic transition. It corresponds to a volume of 90\phantom\rule0.3em0ex\mathrm\AA3 per cell, in good agreement with a previous theoretical analysis in the reduction of volume required to delocalize 5f states.