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Structural behavior of uranium dioxide under pressure by LSDA+U calculations

H. Y. Geng·Y. Chen·Y. Kaneta·M. Kinoshita
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Abstract

The structural behavior of UO2 under high pressure up to 300GPa 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 38GPa. It agrees well with the experimentally observed ~42 GPa. An isostructural transition following that is also predicted to take place from 80 to 130GPa, which has not yet been observed in experiments. Further high compression beyond 226GPa will result in a metallic and paramagnetic transition. It corresponds to a volume of 90A^3 per cell, in good agreement with a previous theoretical analysis in the reduction of volume required to delocalize 5f states.

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H. Y. Geng, Y. Chen, Y. Kaneta, M. Kinoshita. 2007-03-26. Structural behavior of uranium dioxide under pressure by LSDA+U calculations. https://doi.org/10.1103/physrevb.75.054111

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