Modeling of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi mathvariant="normal">Ce</mml:mi><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>,<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mi mathvariant="normal">Ce</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math>, and<mml:ma

Andersson, David; Simak, Sergei I.; Johansson, Börje; Abrikosov, Igor A.; Skorodumova, Natalia V.

doi:10.1103/physrevb.75.035109

Cited by 351 publications

(254 citation statements)

References 34 publications

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“…For the oxygen vacancy, the excess electrons are localized on individual Ce atoms, turning two Ce 4+ into two Ce 3+ species, which, by Coulomb attraction, sit near to the vacancy [29][30][31][32][33][34][35][36][37][38][39][40][41][42]. The results of DFT+U studies are largely dependent on the U value, bringing some uncertainty to the results and raising questions on what value of U should be used to describe the properties of perfect and reduced CeO 2 .…”

Section: Introductionmentioning

confidence: 99%

“…The DFT+U method has also been employed to study the electronic properties of CeO 2 and the impact of oxygen vacancies [29,30,[33][34][35][36][37][38][39][40][41][42]. In this approach, an extra on-site Coulomb interaction is added to the Ce 4f states, leading to a split between occupied and unoccupied states.…”

Section: Introductionmentioning

confidence: 99%

“…For the oxygen vacancy in DFT-LDA or GGA, the excess electrons wind up occupying the narrow 4f band, erroneously leading to delocalized electrons due to the well-known self-interaction error [31][32][33]. The DFT+U method has also been employed to study the electronic properties of CeO 2 and the impact of oxygen vacancies [29,30,[33][34][35][36][37][38][39][40][41][42].…”

Section: Introductionmentioning

confidence: 99%

“…There have appeared numerous studies of bulk CeO 2 based on DFT calculations, many focusing on the oxygen vacancy [10][11][12][13][14][15][16][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42]. DFT calculations using the local density approximation (LDA) or the generalized gradient approximation (GGA) for the exchange-correlation term underestimate the separation between the top of the valence band (O 2p band) and the empty Ce 4f bands in CeO 2 by ~35 % [16,[31][32][33].…”

Section: Introductionmentioning

confidence: 99%

“…DFT calculations using the local density approximation (LDA) or the generalized gradient approximation (GGA) for the exchange-correlation term underestimate the separation between the top of the valence band (O 2p band) and the empty Ce 4f bands in CeO 2 by ~35 % [16,[31][32][33].…”

Section: Introductionmentioning

confidence: 99%

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Disentangling the role of small polarons and oxygen vacancies in CeO2

et al. 2017

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The outstanding performance of cerium oxide (CeO 2 ) as ion conductor or catalyst strongly depends on the ease of Ce 4+ ↔Ce 3+ conversion and oxygen vacancyformation. An accurate description of Ce 3+ and oxygen vacancy is therefore essential to further progress in this area. Using the HSE06 hybrid functional, we investigate the formation and migration of small polarons (Ce 3+ ) and their interaction with oxygen vacancies in CeO 2 , considering the small polaron and vacancy as independent entities.Oxygen vacancies are double donors and can bind up to two small polarons, forming a positively charged or neutral complex. We compute the electron self-trapping energy (i.e., energy gain when forming a small polaron), the small-polaron migration barrier, vacancy formation and migration energies, and vacancy-polaron binding energies. We find that small polarons weakly bind to oxygen vacancies, yet this interaction significantly contributes to the activation energy for hopping electronic conductivity.The results are compared with previous calculations and discussed in the light of available experimental data.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Disentangling the role of small polarons and oxygen vacancies in CeO2

et al. 2017

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Doping OF CeO ₂ as a Tunable Buffer Layer fo Coated Superconductors: A Dft Study of Mechanical and Electronic Properties

Vanpoucke

2015

Developments in Strategic Ceramic Materials

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Ceramic superconductors (CSC) are, just like roof tiles and flower pots, brittle by nature. To fabricate flexible superconducting wires, they are grown as a layered architecture on a metal substrate. Buffer layers are used to prevent metal diffusion and improve lattice matching between the CSC and the substrate. CeO2 is one example of such a buffer layer. To prevent the formation of micro cracks during the fabrication process, doping of CeO2 has been suggested.In this work, we study the influence of dopants (both tetravalent and aliovalent) on the mechanical and structural properties of CeO2 by means of density functional theory (DFT). For tetravalent dopants, a clearly different behavior is found for the group IVa and IVb elements -with the latter acting as stable dopants (i.e. leading to uniform doping) and the former as unstable. This difference is linked to the dopant electronic structure. For all dopants, an inverse relation is observed between the bulk modulus and thermal expansion coefficient. The presence of charge compensating oxygen vacancies is found to modify the dopant influence significantly, often counteracting it. Oxygen vacancies lead to non-linear lattice parameter modifications and strongly reduce the material's bulk modulus.Based on the study of these idealized systems, new dopants are suggested for applications.

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A First‐Principles‐Based Sub‐Lattice Formalism for Predicting Off‐Stoichiometry in Materials for Solar Thermochemical Applications: The Example of Ceria

Gautam

Stechel

Carter

2020

Advcd Theory and Sims

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Theoretical models that reliably can predict off‐stoichiometry in materials via accurate descriptions of underlying thermodynamics are crucial for energy applications. For example, transition‐metal and rare‐earth oxides that can tolerate a large number of oxygen vacancies, such as CeO2 and doped CeO2, can split water and carbon dioxide via a two‐step, oxide‐based solar thermochemical (STC) cycle. The search for new STC materials with a performance superior to that of state‐of‐the‐art CeO2 can benefit from predictions accurately describing the thermodynamics of oxygen vacancies. The sub‐lattice formalism, a common tool used to fit experimental data and build temperature‐composition phase diagrams, can be useful in this context. Here, sub‐lattice models are derived solely from zero‐temperature quantum mechanics calculations to estimate fairly accurate temperature‐ and oxygen‐partial‐pressure‐dependent off‐stoichiometries in CeO2 and Zr‐doped CeO2. Physical motivations for deriving some of the “excess” sub‐lattice model parameters directly from quantum mechanical calculations, instead of fitting to minimize deviations from experimental and/or theoretical data, are identified. Important limitations and approximations of the approach used are specified and extensions to multi‐cation oxides are also suggested to help identify novel candidates for water and carbon dioxide splitting and related applications.

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Modeling ofCeO2,Ce2O3, and

Cited by 351 publications

References 34 publications

Disentangling the role of small polarons and oxygen vacancies in CeO2

Disentangling the role of small polarons and oxygen vacancies in CeO2

Doping OF CeO ₂ as a Tunable Buffer Layer fo Coated Superconductors: A Dft Study of Mechanical and Electronic Properties

A First‐Principles‐Based Sub‐Lattice Formalism for Predicting Off‐Stoichiometry in Materials for Solar Thermochemical Applications: The Example of Ceria

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Modeling ofCeO2,Ce2O3, and

Cited by 351 publications

References 34 publications

Disentangling the role of small polarons and oxygen vacancies in CeO2

Disentangling the role of small polarons and oxygen vacancies in CeO2

Doping OF CeO 2 as a Tunable Buffer Layer fo Coated Superconductors: A Dft Study of Mechanical and Electronic Properties

A First‐Principles‐Based Sub‐Lattice Formalism for Predicting Off‐Stoichiometry in Materials for Solar Thermochemical Applications: The Example of Ceria

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Doping OF CeO ₂ as a Tunable Buffer Layer fo Coated Superconductors: A Dft Study of Mechanical and Electronic Properties