Electron-phonon coupling and superconductivity in the light actinides: A first-principles study

González-Castelazo, P.; Coss-Martínez, R. de; Peña-Seaman, O. De la; Heid, R.; Bohnen, K.‐P.

doi:10.1103/physrevb.93.104512

Cited by 6 publications

(9 citation statements)

References 43 publications

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“…Electronic structure modeling has been extremely useful in understanding the vibrational spectra of nuclear materials, especially for modeling INS data. − Despite significant difficulties with open f-shell systems, density functional theory (DFT) has demonstrated success with regard to predicting the vibrational properties of actinides. − Most relevant to the present work is the combined theoretical and experimental investigation of uranyl fluoride hydrate with INS and DFT by Miskowiec et al In that work, the authors used DFT to predict the phonon spectrum of anhydrous UO 2 F 2 with intercalated waters. By directly predicting the measured dynamic structure factor, they established specific inferences about the coupling of water to certain vibrational modes.…”

Section: Introductionmentioning

confidence: 99%

Inelastic Neutron Spectra of Uranium Tetrafluoride Hydrate, UF₄(H₂O)_2.5

et al. 2021

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Uranium tetrafluoride hydrate (UFH) is formed by immersing anhydrous UF4 under water for 12 h. UFH is therefore clearly a chemical species of environmental concern, as anhydrous UF4 is an intermediate uranium form in the nuclear fuel cycle. We use inelastic neutron scattering (INS) to probe the full vibrational spectra of UFH and its deuterated analogue in an effort to improve the fundamental understanding of its vibrational spectra. Coupled with density functional theory (DFT) calculations, the first for this compound, and full spectral modeling, we generate the complete vibrational spectra of UFH and compare them to prior optical spectroscopic results. In particular, the combination of DFT with INS allows us to identify multiple distinct chemical environments in the water bending and OH stretching regions. Whereas the water molecules directly bound to the U atoms execute OH stretching around 3600 cm–1, a second class of H-bonded waters vibrate below 3000 cm–1, an indicator of strong H bonding. In addition, a class of librational water modes are observed between 400 and 900 cm–1, which themselves can be separated in energy according to their chemical environments. Measurements presented herein directly assist in the assignment of certain spectral features in the infrared spectrum and will inform future investigations of UFH for environmental or forensics purposes.

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Section: Introductionmentioning

confidence: 99%

Inelastic Neutron Spectra of Uranium Tetrafluoride Hydrate, UF₄(H₂O)_2.5

et al. 2021

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“…Among the elements of this family, Th has been studied the most. Several theoretical investigations in literature address its crystal structure [3][4][5][6][7][8][9][10][11] as well as its electronic properties [12][13][14][15][16]. For Ac much less information is available about its structural and electronic properties.…”

Section: Introductionmentioning

confidence: 99%

“…In both cases, the importance of relativistic effects, including spin-orbit coupling (SOC), is manifested. Additionally, it has been reported that including f states in the electronic states expansion is important for stabilizing the fcc structure, despite the fact that their energy lies just above the Fermi level (E F ) with a very small contribution to the density of states at E F [16][17][18].…”

Section: Introductionmentioning

confidence: 99%

“…For Th, the results from calculations [25][26][27][28], although not including spin-orbit coupling (SOC) explicitly, are, in general, in agreement with experimental data. SOC has been taken into account only in a recent study of the lattice dynamical properties of Ac and Th, which found a slight hardening of the phonon spectrum in comparison with standard scalar relativistic (SR) calculations [16].…”

Section: Introductionmentioning

confidence: 99%

“…For Ac there are no information about T c or the coupling strength because Ac is highly radioactive and poisonous, and in addition a rare and expensive element. From the theory side, very few papers have studied the e-ph coupling of 5f systems [16,31,32,35] so far, mainly because adequate models and theories capable of dealing with them were lacking. One early work addressed the e-ph coupling of the light actinide series in a systematic way [32].…”

Section: Introductionmentioning

confidence: 99%

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Effect of doping on lattice dynamics and electron–phonon coupling of the actinides Ac–Th alloy

Coss-Martínez

González-Castelazo

Peña-Seaman

et al. 2017

J. Phys.: Condens. Matter

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We have studied the electronic, lattice dynamical, and electron-phonon properties of the actinides [Formula: see text]Th alloy within the framework of density functional perturbation theory. The self-consistent virtual crystal approximation is used for the alloy modeling, and spin-orbit coupling is included in the calculation of all relevant quantities. An overall decrease of the electron-phonon coupling (λ) by [Formula: see text] from Ac to Th was observed. However, its dependence on x shows a non-linear behavior. λ reduces just 6% from Ac to a Th content of [Formula: see text], then drops drastically (∼[Formula: see text]) from there until [Formula: see text]. The large decrease of λ for [Formula: see text] is due to the reduction of the density of states at the Fermi level ([Formula: see text]), combined with a general phonon hardening. On contrast, the behavior for [Formula: see text] is the result of a subtle balance between an enhancement of phase space and the above mentioned effects on [Formula: see text] and the phonons. The phase-space enhancement is related to the appearance of Kohn anomalies, which fade away as the Th concentration increases.

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Effective Coulomb interaction in actinides from linear response approach

Qiu

2020

Computational Materials Science

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The effective on-site Coulomb interaction (Hubbard U ) between 5f electrons in actinide metals (Th-Cf) is calculated with the framework of density-functional theory (DFT) using linear response approach. The U values seldom rely on the exchange-correlation functional, spin-orbital coupling, and magnetic states, but depend on the lattice volume and actinide element. Along the actinide series, the Coulomb parameter U of α-phase first decreases slowly, followed by a jump in the vicinity of Pu and then a monotonous increase. For light actinides, the lattice volume has a sizeable influence on U while the localization of 5f electrons is almost constant. But for transplutonium metals, U is almost independent of the lattice volume but the electronic localization increases rapidly. The calculated lattice parameters from DFT+U with the Coulomb parameters as input are in better agreement with the experimental values than those from DFT within local density approximation or Perdew-Burke-Ernzerhof approximation for solids (PBEsol). In particular, the agreement between PBEsol+U and experiment is remarkable. We show that PBEsol+U also well reproduce the experimental bulk moduli and the transition from itinerancy to localization of 5f electrons along the series. Therefore it is concluded that DFT+U with U calculated from linear response approach is suitable for a good description of actinide metals.

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Electron-phonon coupling and superconductivity in the light actinides: A first-principles study

Cited by 6 publications

References 43 publications

Inelastic Neutron Spectra of Uranium Tetrafluoride Hydrate, UF₄(H₂O)_2.5

Inelastic Neutron Spectra of Uranium Tetrafluoride Hydrate, UF₄(H₂O)_2.5

Effect of doping on lattice dynamics and electron–phonon coupling of the actinides Ac–Th alloy

Effective Coulomb interaction in actinides from linear response approach

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Electron-phonon coupling and superconductivity in the light actinides: A first-principles study

Cited by 6 publications

References 43 publications

Inelastic Neutron Spectra of Uranium Tetrafluoride Hydrate, UF4(H2O)2.5

Inelastic Neutron Spectra of Uranium Tetrafluoride Hydrate, UF4(H2O)2.5

Effect of doping on lattice dynamics and electron–phonon coupling of the actinides Ac–Th alloy

Effective Coulomb interaction in actinides from linear response approach

Contact Info

Product

Resources

About

Inelastic Neutron Spectra of Uranium Tetrafluoride Hydrate, UF₄(H₂O)_2.5

Inelastic Neutron Spectra of Uranium Tetrafluoride Hydrate, UF₄(H₂O)_2.5