First-principles study of compensation mechanisms in negatively charged LaGaO<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mn>3</mml:mn></mml:msub></mml:math>/MgAl<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mn>2</mml:mn></mml:msub></mml:math>O<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mn>4</mml:mn></mml:msub></mml:math>interfaces

Rébola, Alejandro; Fong, Dillon D.; Öğüt, Serdar; Zapol, Peter

doi:10.1103/physrevb.87.245117

Cited by 15 publications

(12 citation statements)

References 40 publications

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“…The lattice parameters of the optimized structure with the 5/3 unit cell are shown in Table I. The results are essentially the same as those obtained by Rébola et al 17 and agree well with experimental data. or Ca atoms.…”

Section: B Computational Methodssupporting

confidence: 86%

“…2. After structural relaxation, we find a clustering with three units of Ca 2 CoO 3 (denoted by X 3 ) along the b axis of the RS subsystem, which is a feature also observed by Rébola et al 17 . Due to this clustering, the CoO 6 octahedra on the either side of X 3 are significantly distorted.…”

Section: B Computational Methodssupporting

confidence: 82%

“…Calculated lattice parameters (in Å) for the 5/3 approximant of bulk CCO compared with previous calculations of Rébola et al17 and experimental data taken from Miyazaki et al 7 . b RS and b CoO 2 are the lattice constants along the b-axis for the RS and CoO 2 subsystems, respectively.…”

mentioning

confidence: 79%

“…were carried out using the Perdew-Burke-Ernzerhof (PBE) 36,37 exchange correlation functional and the plane-wave pseudopotential method as implemented in the Vienna Ab Initio Simulation Package (VASP) 38 . Rébola et al 17,18 suggested that the incommensurately layered CCO can be modeled using rational approximants of composition [Ca…”

Section: B Computational Methodsmentioning

confidence: 99%

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Atomic and electronic structure of Ti substitution in Ca3Co4O9

Phillips

Mazumdar

et al. 2016

Journal of Applied Physics

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We examine the role of Ti doping in the incommensurately layered thermoelectric oxide material Ca 3 Co 4 O 9 (CCO). The measured Seebeck coefficient of S = 135 µV /K in Ti-doped CCO thin films of composition Ca 3 Co 3.8 Ti 0.2 O 9 indicates no significant enhancement of S compared to pristine CCO, thus confirming prior experimental results. Using a combination of aberration-corrected scanning transmission electron microscopy, electron energy-loss spectroscopy and first-principles computations, we determine the atomic and electronic structures of Ti-doped CCO, including the preferred location of Ti dopants and valence states of Ti and Co atoms. Our findings on the structural, electronic and transport properties of the Ti-doped CCO are discussed in light of previously published results.

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Section: B Computational Methodssupporting

confidence: 86%

Section: B Computational Methodssupporting

confidence: 82%

mentioning

confidence: 79%

Section: B Computational Methodsmentioning

confidence: 99%

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Atomic and electronic structure of Ti substitution in Ca3Co4O9

Phillips

Mazumdar

et al. 2016

Journal of Applied Physics

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“…where spinel demonstrates remarkable resistance to formation of structural damages caused by neutrons and light ions, e.g., amorphous microareas inside MgAl2O4 lattice, which essentially weaken further penetration of irradiation; (ii) defective spinel crystals, colored or colorless, in dependence on what kind of point defects is prevailing in them (neutral or charged vacancies, native interstitials and anti-sites, impurity substitutes, pair-wise defects, etc. ), used in different electronic and optical devices [9][10][11] (as to irradiation in the range of visible spectrum, just presence of F centers is mainly responsible for it); (iii) supporting material for catalytic reactions possessing long-term durability [12,13] (it was found that oxygen vacancies at its surface layers of support play prominent role in dispersion of catalytic metal nanoclusters, their migration and stabilization); (iv) thin films of Mg-spinel used in humidity-measured devices [14].…”

Section: Introductionmentioning

confidence: 99%

Site symmetry approach applied to the supercell model of MgAl2O4 spinel with oxygen interstitials: Ab initio calculations

Ėvarestov

Platonenko

Zhukovskii

2018

Computational Materials Science

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In this study we simulate structural, electronic and phonon properties of MgAl2O4 spinel containing single oxygen interstitial (Oi) per crystalline L4 and L8 supercells, e.g., its dumbbell configuration formed with one of the nearest regular oxygen atoms of the lattice (Oi-Oreg). Due to the splitting of the Wyckoff positions in supercell models of perfect crystal, five possible Oi positions with different site symmetry have been identified and studied (C1, Cs, C3v D2d and Td). First principles hybrid HSE06 DFT functional calculations on perfect and defective spinel structures have been accompanied by geometry optimization. The calculated properties of spinel crystal (lattice constants, bulk modulus, band gap as well as frequencies of infraredand Raman-active vibrational modes) qualitatively well agree with the corresponding experimental data. The formation energy of Oi is found to be minimal for the interstitial site of lowest symmetry (C1). The results obtained are important, in particular, for understanding the radiation and chemical stability as well as other key properties of MgAl2O4 spinel-type oxide crystals.

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Understanding the Highly Electrocatalytic Active Mixed Triple Conducting Na_xCa_3–_xCo₄O_9–δ Oxygen Electrode Materials

Park

Bae

Kim

et al. 2022

Advanced Energy Materials

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Despite their high electrocatalytic activity for oxygen electrode reactions, the low phase stability and high thermal expansion of perovskite structured materials have created difficulties in cell fabrication scale‐up and long‐term operational stability of reversible ceramic cells. Herein, an exceptionally high‐performance electrocatalyst is presented based on a misfit‐layered structure, Na0.15Ca2.85Co4O9–δ (NCCO). NCCO cells enable exceptional fuel cell performance down to 400 °C, with peak power densities of 0.18–5.15 W cm−2 at 400–800 °C, as well as electrolysis performance of minus current density 5.96–15.07 A·cm−2 (at 1.4 V) at 600–750 °C, exceeding the values of all previously described reversible (oxygen and proton) ceramic cells. Furthermore, the durability of NCCO cells is demonstrated for over 900 h at high current densities of 1 and 2 A cm−2 in fuel cells and –0.5 and –4 A cm−2 electrolysis cell modes under load cycle and constant current reversible operation, respectively. Doping with basic monovalent Na+ ions in the Ca‐site in Ca3Co4O9+δ generates a high density of extra charge carrier species with the increased Co oxidation state and facilitates the proton uptake and diffusion properties of misfit‐layered materials. This finding can deliver a new opportunity to develop innovative bifunctional oxygen electrode catalysts, while providing more favorable reaction pathways for the diffusion of charged species.

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First-principles study of compensation mechanisms in negatively charged LaGaO3/MgAl2O4interfaces

Cited by 15 publications

References 40 publications

Atomic and electronic structure of Ti substitution in Ca3Co4O9

Atomic and electronic structure of Ti substitution in Ca3Co4O9

Site symmetry approach applied to the supercell model of MgAl2O4 spinel with oxygen interstitials: Ab initio calculations

Understanding the Highly Electrocatalytic Active Mixed Triple Conducting Na_xCa_3–_xCo₄O_9–δ Oxygen Electrode Materials

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First-principles study of compensation mechanisms in negatively charged LaGaO3/MgAl2O4interfaces

Cited by 15 publications

References 40 publications

Atomic and electronic structure of Ti substitution in Ca3Co4O9

Atomic and electronic structure of Ti substitution in Ca3Co4O9

Site symmetry approach applied to the supercell model of MgAl2O4 spinel with oxygen interstitials: Ab initio calculations

Understanding the Highly Electrocatalytic Active Mixed Triple Conducting NaxCa3–xCo4O9–δ Oxygen Electrode Materials

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Product

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Understanding the Highly Electrocatalytic Active Mixed Triple Conducting Na_xCa_3–_xCo₄O_9–δ Oxygen Electrode Materials