Structural, electronic and energetic properties of uranium–americium mixed oxides ${\rm U}_{1-y}{\rm Am}_y{\rm O}_2$ using DFT$+{U}$ calculations - Archive ouverte HAL Access content directly
Journal Articles Journal of Physics: Condensed Matter Year : 2019

Structural, electronic and energetic properties of uranium–americium mixed oxides ${\rm U}_{1-y}{\rm Am}_y{\rm O}_2$ using DFT$+{U}$ calculations

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Abstract

In this paper, we determine for the fjrst time the electronic, structural and energetic properties of U 1−y Am y O 2 mixed oxides in the entire range of Am content using the generalized gradient approximation (GGA) +U in combination with the special quasirandom structure (SQS) approach to reproduce chemical disorder. This study reveals that in U 1−y Am y O 2 oxides, Am cations act as electron acceptors, whereas U cations act as electron donors showing a fundamental difference with U 1−y Pu y O 2 or U 1−y Ce y O 2 in which there is no cation valence change in stoichiometric conditions compared to the pure oxides. We show for the fjrst time that the lattice parameter of stoichiometric U 1−y Am y O 2 follows a linear evolution which is the structural signature of an ideal solid solution behavior. Finally, using two approaches (SQS and parametric), we show by assessing the enthalpy of mixing that there is no phase separation in the whole range of Am concentration.
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Dates and versions

cea-02535457 , version 1 (02-02-2022)

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Attribution - NonCommercial - CC BY 4.0

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Martin S. Talla Noutack, Gérald Jomard, Michel Freyss, Grégory Geneste. Structural, electronic and energetic properties of uranium–americium mixed oxides ${\rm U}_{1-y}{\rm Am}_y{\rm O}_2$ using DFT$+{U}$ calculations. Journal of Physics: Condensed Matter, 2019, 31 (48), pp.485501. ⟨10.1088/1361-648X/ab395e⟩. ⟨cea-02535457⟩
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