DFT+U study of the structures and properties of the actinide dioxides

Pegg, James; Aparicio-Anglès, Xavier; Storr, Mark T.; Leeuw, Nora H. de

doi:10.1016/j.jnucmat.2017.05.025

Cited by 96 publications

(112 citation statements)

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“…The uranium (6s 2 , 7s 2 , 6p 6 , 6d 2 5f 2 ), neptunium (6s 2 , 7s 2 , 6p 6 , 6d 2 5f 3 ), and oxygen (2s 2 , 2p 4 ) valence electrons are implicitly considered, as are the SOI 13 and contributions to noncollinear magnetic wave-vectors. The cut-off energy and k-point grid for each calculation have been 7 validated in our previous work 32 and the conjugate gradient algorithm has been used to evaluate the ionic forces. 112 Images are visualized by the VESTA code.…”

Section: Calculation Detailsmentioning

confidence: 99%

“…116 In the past, the influence of J on noncollinear magnetic materials, and the performance of numerous exchangecorrelation functionals, has been investigated. 32,116 Therefore we have kept the J modifier at a constant value of 0.00 eV and referenced against past investigations. 32…”

Section: Calculation Detailsmentioning

confidence: 99%

“…22-29 A key difficulty in the computational investigation of the AnO2 is the treatment of relativistic effects, electron-correlation, and complex magnetic structures. The correct electronic structure of the AnO2 cannot be calculated by conventional density functional theory (DFT) based methods, 30,31 due to the high degree of electron-correlation, 32 which often manifests as an underestimation of the electronic band-gap. 9,33 To compensate, numerous methods have been developed such as, the self-interaction correction (SIC) method, 34 modified density functional theory (DFT+U), 30,31,[35][36][37] dynamic mean field theory (DMFT), 38 and hybrid density functionals.…”

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confidence: 99%

“…47,48 In the majority of cases, due to the computational expense of modelling these systems, AnO2 studies have been restricted to discussions of collinear 1k magnetic order due to the computational expense of the systems. 9,33,41,[48][49][50][51][52][53][54][55][56][57][58][59][60] In addition, although the importance of spin-orbit interactions (SOI) 13 for the treatment of the actinide elements has been highlighted in numerous investigations, 32,47 few consider SOI effects in their fully relativistic studies. 33,45,47,[58][59][60][61] The magnetic structure of UO2 displays interesting characteristics.…”

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confidence: 99%

“…19,68,71,73 , which is indicative of transverse 3k AFM order. 32,73,74 Antiferroquadrupolar ordering favours Pa3 ̅ (No. 205) crystal symmetry by minimizing quadrupolar and exchange terms.…”

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confidence: 99%

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Magnetic Structure of UO2 and NpO2 by First-Principle Methods

Pegg¹,

Shields²,

Storr³

et al. 2018

Preprint

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The magnetic structure of the actinide dioxides (AnO2) remains a subject of intense research and is key to the development of high-accuracy computational models. A low-temperature experimental investigation of the magnetic ground-state is complicated by thermal energy released from the radioactive decay of the actinide nuclei. To establish the magnetic groundstate, we have employed high-accuracy computational methods to systematically probe different magnetic structures. A transverse 1k antiferromagnetic ground-state with Fmmm (No. 69) crystal symmetry has been established for UO2, whereas a ferromagnetic (111) ground-state with R3 ̅ m (No. 166) has been established for NpO2. This has a profound impact on future computational investigations. Band structure calculations have been performed to analyse these results.

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Section: Calculation Detailsmentioning

confidence: 99%

Section: Calculation Detailsmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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confidence: 99%

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Magnetic Structure of UO2 and NpO2 by First-Principle Methods

Pegg¹,

Shields²,

Storr³

et al. 2018

Preprint

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Actinides: Electronic Structure of the Oxides

Roy

2018

Encyclopedia of Inorganic and Bioinorganic Chemistry

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This article outlines the recent work in using density functional methods to describe the structure and properties of the actinide oxides. The area represents a rich research history of using various methods such as local‐density approximation/generalized gradient approximation (LDA/GGA), modified density functional theory (DFT+ U ), self‐interaction correction methods (SIC), density functional theory + dynamic mean field theory (DFT+DMFT), and hybrid density functional theory (HSE) to assess the accuracy of predicting the properties of the oxides. Herein, the methods are assessed with respect to their accuracy in predicting the lattice constants, bulk moduli, band gap, and volumes based on experiment. Of the oxides, the dioxides represent the most complete analysis of the actinide series; of the elements, the most comprehensive study of structure–property relationships has been performed for the uranium oxides; and of the methods, DFT+ U has been able to accurately reproduce the known properties of the actinide oxides at a reasonable computational cost. While the issues associated with theoretical methods remain challenging, it is clear that the field will continue to push the bounds and ultimately lead to a predictive science for development of new nuclear materials.

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Interband Transitions and Critical Points of Single‐Crystal Thoria Compared with Urania

Dugan

Wang

Zhang

et al. 2022

Physica Status Solidi (b)

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The interband transitions of UO2 are validated independently through cathode luminescence. A picture emerges consistent with density functional theory. While theory is generally consistent with experiment, it is evident from the comparison of UO2 and ThO2 that the choice of functional can significantly alter the bandgap and some details of the band structure, in particular at the conduction band minimum. Strictly ab initio predictions of the optical properties of the actinide compounds, based on density functional theory alone, continue to be somewhat elusive.

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DFT+U study of the structures and properties of the actinide dioxides

Cited by 96 publications

References 109 publications

Magnetic Structure of UO2 and NpO2 by First-Principle Methods

Magnetic Structure of UO2 and NpO2 by First-Principle Methods

Actinides: Electronic Structure of the Oxides

Interband Transitions and Critical Points of Single‐Crystal Thoria Compared with Urania

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