First-principle study of B1-like thorium carbide, nitride and oxide

Shein, I. R.; Shein, K. I.; Ivanovskiĭ, A. L.

doi:10.1016/j.jnucmat.2006.02.075

Cited by 54 publications

(52 citation statements)

References 23 publications

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“…They are all positive, which indicates that the compounds are all elastically stable. The inclusion of the U parameter leads to an overall better agreement of the calculated elastic properties with other available theoretical and experimental data [41,42,22,8]. For instance, the experimentally determined bulk modulus and the calculated result of our lowest energy structure in parenthesis for ThN and UN are 175 GPa [43] (178 GPa) and 193 GPa [41] (198 GPa) respectively.…”

Section: Elastic Propertiessupporting

confidence: 55%

GGA+U studies of the early actinide mononitrides and dinitrides

Obodo

Chetty

2013

Journal of Nuclear Materials

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Abstract. We present a detailed comparative study of the electronic and mechanical properties of the early actinide mononitrides and dinitrides within the framework of the Perdew-Burke-Ernzerhof generalized gradient approximation (GGA [PBE]) and GGA + U implementations of density functional theory with the inclusion of spin-orbit coupling. The dependence of selected observables of these materials on the effective U-parameter is investigated in detail. The properties include the lattice constant, bulk modulus, charge density distribution, hybridization of the atomic orbitals, energy of formation and the lattice dynamics. The inclusion of the Hubbard U parameter results in a proper description of the 5f electrons, and is subsequently used in the determination of the structural and electronic properties of these compounds. The mononitrides and dinitrides of the early actinides are metallic except for UN 2 , which is a semiconductor. These actinide nitrides are non-magnetic with the exception of UN, NpN, PuN, NpN 2 and PuN 2 that are magnetic systems with orbital-dependent magnetic moments oriented in the z-axis. We observed that ThN 2 is elastically unstable to isotropic pressure. We discovered that UN 2 is thermodynamically unstable, but may be stabilized by N vacancy formation.

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Section: Elastic Propertiessupporting

confidence: 55%

GGA+U studies of the early actinide mononitrides and dinitrides

Obodo

Chetty

2013

Journal of Nuclear Materials

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“…Recently, Sedmidubsky et al [8] calculated the enthalpies of formation of the actinide mononitride series using a full-potential linear augmented plane wave plus local basis (FP -LAPW + lo) [17] with the generalized gradient approximation [18] within the frame work of density functional theory (DFT). [20] have studied the electronic structure properties of cubic ThC, ThN, and ThO using the FP -LAPW + lo method within the GGA -DFT approximation.…”

Section: Introductionmentioning

confidence: 99%

Density functional study of the actinide nitrides

2007

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The full potential all electron linearized augmented plane wave plus local orbitals (FP-LAPW + lo) method, as implemented in the suite of software WIEN2K, has been used to systematically investigate the structural, electronic, and magnetic properties of the actinide compounds AnN (An = Ac, Th, Pa, U, Np, Pu, Am). The theoretical formalism used is the generalized gradient approximation to density functional theory (GGA-DFT) with the Perdew-Burke-Ernzerhof (PBE) exchange-correlation functional.Each compound has been studied at six levels of theory: non-magnetic (NM), non-

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“…The exchange-correlation functional with the generalized gradient approximation (GGA) of Perdew-Burke-Ernzerhof (PBE) 22 was used to solve the Kohn-Sham equations with a kinetic energy cutoff of 600 eV. Since none of the localized 5f -like bands is occupied in Th, the DFT-GGA level calculations provide adequate description for the structural and vibrational properties of Th and its compounds [23][24][25][26] . We performed global structural optimization for ThS 2 by combining first-principles total energy calculations and the particle-swarm optimization (PSO) algorithm 17 on structural prediction as implemented in the CALYPSO code 27 , which has been proved to be effective and accurate in predicting the crystal structures of a large variety of materials [28][29][30][31][32][33][34][35] .…”

Section: Methodsmentioning

confidence: 99%

Structural and electronic phase transitions ofThS2from first-principles calculations

et al. 2016

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Thorium and its compounds have received considerable attention in recent years due to the renewed interest in developing the thorium fuel cycle as an alternative nuclear energy technology. There is pressing current need to explore the physical properties essential to the fundamental understanding and practical application of these materials. Here we report on a computational study of thorium disulfide (ThS2), which plays an important role in the thorium fuel reprocessing cycle. We have employed the density functional theory and evolutionary structure search methods to determine the crystal structures, electronic band structures, phonon dispersions and density of states, and thermodynamic properties of ThS2 under various pressure and temperature conditions. Our calculations identify several crystalline phases of ThS2 and a series of structural phase transitions induced by pressure and temperature. The calculated results also reveal electronic phase transitions from the semiconducting state in the low-pressure phases of ThS2 in the P nma and F m3m symmetry to the metallic state in the high-pressure phases of ThS2 in the P nma and I4/mmm symmetry. These results explain the experimental observation of the thermodynamic stability of the P nma phase of ThS2 at the ambient conditions and a pressure-induced structural phase transition in ThS2 around 40 GPa. Moreover, the present study reveals considerable additional information on the structural and electronic properties of ThS2 in a wide range of pressure and temperature. Such information provides key insights into the fundamental material behavior and the underlying mechanisms that lay the foundation for further exploration and application of ThS2.

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First-principle study of B1-like thorium carbide, nitride and oxide

Cited by 54 publications

References 23 publications

GGA+U studies of the early actinide mononitrides and dinitrides

GGA+U studies of the early actinide mononitrides and dinitrides

Density functional study of the actinide nitrides

Structural and electronic phase transitions ofThS2from first-principles calculations

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