Relativistic effects in the study of structure and electronic properties of UO2 within DFT+U method

Payami Shabestar, Mahmoud; Sheykhi, Samira

doi:10.47176/ijpr.23.3.11777

Relativistic effects in the study of structure and electronic properties of UO2 within DFT+U method

Document Type : Original Article

Authors

Mahmoud Payami Shabestar

Samira Sheykhi

School of Physics and Accelerators, Nuclear Science and Technology Research Institute, AEOI, P.O. Box 14395-836, Tehran, Iran

https://doi.org/10.47176/ijpr.23.3.11777

Abstract

Electrons of orbitals near to nuclei of heavy atoms acquire speeds comparable to the speed of light in vacuum. Therefore, to study the properties of crystals containing heavy atoms, it is necessary to take into account the relativistic effects. In this work, using the first-principles DFT+U method, we have calculated the electronic structure and geometric properties of uranium dioxide UO₂ within full-relativistic, scalar-relativistic, and non-relativistic formulations, and compared the results. It is shown that: (i) the non-relativistic scheme gives results very far form experimental values for both lattice constant and bang gap; (ii) in full-relativistic case which the spin-orbit effects are included, the Kohn-Sham band-gap is increased by 6.2% and the lattice constant decreases by 0.05% compared to scalar-relativistic one. Therefore, in the study of geometric properties of UO_2, using the scalar-relativistic regime is quite accurate and one does not need to perform much more expensive full-relativistic calculations whenever one does not study the electronic excitation properties.

Keywords

uranium dioxide

anti-ferromagnetism

density-functional theory

spin-orbit effect

Mott insulator

DFT+U

Subjects

Condensed Matter Physics

G Amoretti, et al., Rev. B 40 (1989) 1856.
J Faber, G H Lander, and B R Cooper, Rev. Lett. 35 (1975) 1770.
M Idiri, T Le Bihan, S Heathman, and J Rebizant, Rev. B 70 (2004) 014113.
L Y Desgranges, Ph Ma, G Garcia, D Baldinozzi, and H E F Simeone, Chem. 56 (2017) 321.
Y Baer and J Schoenes, Solid State Commun. 33 (1980) 885.
J Schoenes, Appl. Phys. 49 (1978) 1463.
V A Gubanov, A Rosen, and D E Ellis, Solid State Commun. 22 (1977) 219.
S L Dudarev, et al, Physica status solidi (a) 166 (1998) 429.
J Schoenes, Rep. 63 (1980) 301.
S L Dudarev, D N Manh, and A P Sutton, Mag. B 75 (1997) 613.
B Dorado, B Amadon, M Freyss, and M Bertolus, Rev. B 79 (2009) 235125.
J T Pegg, X Aparicio-Angles, M Storr, and N H de Leeuw, Nora, Nucl. Materials 492 (2017) 269.
S Sheykhi and M Payami, Physica C: Superconductivity and its Applications 549 (2018) 93.
M S Christian, E R Johnson, and T M Besmann, Phys. Chem. A 125 (2021) 2791.
P Hohenberg and W Kohn, Rev. 136 (1964) B864.
W Kohn and L J Sham, Rev. 140 (1965) A1133.
M Cococcioni and S de Gironcoli, Rev. B 71 (2005) 035105.
B Himmetoglu, A Floris, S de Gironcoli, and M Cococcioni, J. Quantum Chem. 114 (2014) 14.
M Freyss, B Dorado, et al., Scientific Highlight of The Month 113 (2012).
R A Evarestov, A I Panin, and A V Bandura, Russian J. General Chem. 78 (2008) 1823.
M J T Oliveira and F Nogueira, Phys. Commun. 178 (2008) 524.
D D Koelling and B N Harmon, Phys. C: Solid State Physics 10 (1977) 3107.
P Giannozzi, et. al., Phys.: Condens. Matter 21 (2009) 395502.
P Giannozzi, et. al., Chem. Phys. 152 (2020) 154105.
M P Methfessel and A T Paxton, Rev. B 40 (1989) 3616.
P E Blochl, O Jepsen, and O K. Andersen, Rev. B 49 (1994) 16223.
M Payami, arXiv:2302.04231v1[cond-mat.mtrl-sci] (2023).
J P Perdew, A Ruzsinszky, G I Csonka, O A Vydrov, G E Scuseria, L A Constantin, X Zhou, and K Burke, Rev. Lett. 100 (2008) 136406.
J P Perdew, A Ruzsinszky, G I Csonka, O A Vydrov, G E Scuseria, L A Constantin, X Zhou, and K Burke, Rev. Lett. 102 (2009) 039902.