GGA+U study of uranium mononitride: A comparison of the U-ramping and occupation matrix schemes and incorporation energies of fission products

Antoine Claisse; Marco Klipfel; Niclas Lindbom; Michel Freyss; Pär Olsson

GGA+U study of uranium mononitride: A comparison of the U-ramping and occupation matrix schemes and incorporation energies of fission products

Antoine Claisse ^{1, *} Marco Klipfel ² Niclas Lindbom ¹ Michel Freyss ³ Pär Olsson ¹

* Corresponding author

1 KTH - Royal Institute of Technology [Stockholm]

2 JRC - European Commission - Joint Research Centre [Karlsruhe]

3 DEC - Département d'Etudes des Combustibles

Abstract : Uranium mononitride is studied in the DFT + U framework. Its ground state is investigated and a study of the incorporation of diverse fission products in the crystal is conducted. The U-ramping and occupation matrix control (OMC) schemes are used to eliminate metastable states. Beyond a certain amount of introduced correlation, the OMC scheme starts to find a lower total energy. The OMC scheme is chosen for the second part of this study. Furthermore, the influence of the magnetic ordering is studied using the U-ramping method, showing that antiferromagnetic order is the most stable one when the U parameter is larger than 1.75 eV. The effect on the density of states is investigated and elastic constants are provided for comparison with other methods and experiments. The incorporation energies of fission products in different defect configurations are calculated and these energies are corrected to take into account the limited size of the supercell.

Document type :

Journal articles

Domain :

Physics [physics]

Physics [physics] / Condensed Matter [cond-mat]

Physics [physics] / Condensed Matter [cond-mat] / Materials Science [cond-mat.mtrl-sci]

Physics [physics] / Condensed Matter [cond-mat] / Strongly Correlated Electrons [cond-mat.str-el]

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https://hal-cea.archives-ouvertes.fr/cea-02063633
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Submitted on : Monday, March 11, 2019 - 12:59:50 PM
Last modification on : Wednesday, March 13, 2019 - 1:23:25 AM
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GGA+U study of uranium mononitride: A comparison of the U-ramping and occupation matrix schemes and incorporation energies of fission products

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