Intrinsic point-defect equilibria in tetragonal ZrO<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>: Density functional theory analysis with finite-temperature effects

Youssef, Mostafa; Yildiz, Bilge

doi:10.1103/physrevb.86.144109

Cited by 80 publications

(67 citation statements)

References 71 publications

(73 reference statements)

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“…The energies of each image were calculated using density functional theory (DFT) with Vienna Ab initio Simulation Package (VASP) [26][27][28][29] with a 2 × 2 × 2 supercell and a 2 × 2 × 2 k-point grid. The generalized gradient approximation (GGA) with a Perdew-Burke-Ernzerhof (PBE) functional [30,31] [24,16,32].…”

Section: Methodsmentioning

confidence: 99%

“…In previous work, by combining first-principles-based pointdefect calculations with statistical thermodynamics, we were able to predict equilibrium defect concentrations at various temperatures and oxygen partial pressures both in tetragonal [24] and monoclinic ZrO 2 [16]. Here we calculated the migration barriers of different oxygen defect types and migration paths by first-principles calculations.…”

Section: Introductionmentioning

confidence: 99%

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Oxygen self-diffusion mechanisms in monoclinic ZrO2 revealed and quantified by density functional theory, random walk analysis, and kinetic Monte Carlo calculations

2018

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In this work, we quantify oxygen self-diffusion in monoclinic-phase zirconium oxide as a function of temperature and oxygen partial pressure. A migration barrier of each type of oxygen defect was obtained by first-principles calculations. Random walk theory was used to quantify the diffusivities of oxygen interstitials by using the calculated migration barriers. Kinetic Monte Carlo simulations were used to calculate diffusivities of oxygen vacancies by distinguishing the threefold-and fourfold-coordinated lattice oxygen. By combining the equilibrium defect concentrations obtained in our previous work together with the herein calculated diffusivity of each defect species, we present the resulting oxygen self-diffusion coefficients and the corresponding atomistically resolved transport mechanisms. The predicted effective migration barriers and diffusion prefactors are in reasonable agreement with the experimentally reported values. This work provides insights into oxygen diffusion engineering in ZrO 2 -related devices and parametrization for continuum transport modeling.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Oxygen self-diffusion mechanisms in monoclinic ZrO2 revealed and quantified by density functional theory, random walk analysis, and kinetic Monte Carlo calculations

2018

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“…In several cases, hybrid functionals have been shown to outperform other functionals in describing electronic structure and optical properties of materials, and thus, they were assumed to be accurate and superior in all other cases. This opinion was recently disputed by many authors like Youssef and Yildiz 19 and Ramprasad et al 20 who argued that given the known underestimation of formation energies by PBE, hybrid functionals does overestimate them in many cases. Another reason we chose not to use hybrid functionals is that here our focus is not entirely on the absolute values of the formation energies but rather the trends produced by changes in the composition from group III to group V as will be shown in Sec.…”

Section: Methodology a Computational Detailsmentioning

confidence: 99%

Vacancies and defect levels in III–V semiconductors

Tahini

Chroneos

Murphy

et al. 2013

Journal of Applied Physics

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Using electronic structure calculations, we systematically investigate the formation of vacancies in III-V semiconductors (III ¼ Al, Ga, and In and V ¼ P, As, and Sb), for a range of charges (À3 q 3) as a function of the Fermi level and under different growth conditions. The formation energies were corrected using the scheme due to Freysoldt et al. [Phys. Rev. Lett. 102, 016402 (2009)] to account for finite size effects. Vacancy formation energies were found to decrease as the size of the group V atom increased. This trend was maintained for Al-V, Ga-V, and In-V compounds. The negative-U effect was only observed for the arsenic vacancy in GaAs, which makes a charge state transition from þ1 to -1. It is also found that even under group III rich conditions, group III vacancies dominate in AlSb and GaSb. For InSb, group V vacancies are favoured even under group V rich conditions. V C 2013 AIP Publishing LLC.

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“…[39,43,29,5,2,3]), focusing significantly less on the most stable m-ZrO 2 form. Foster et al reported an evaluation of charged and neutral vacancies in the m-ZrO 2 bulk.…”

Section: Introductionmentioning

confidence: 99%

Understanding Structure and Stability of Monoclinic Zirconia Surfaces from First-Principles Calculations

Bazhenov

Honkala

2016

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Under the water-rich pre-treatment and/or reaction conditions, structure and chemistry of the monoclinic zirconia surfaces are strongly influenced by oxygen vacancies and incorporated water. Here, we report a combined first-principles and atomistic thermodynamics study on the structure and stability of selected surfaces of the monoclinic zirconia. Our results indicate that among the studied surfaces, the most stable (111) surface is the least vulnerable towards oxygen vacancies in contrast to the less stable (011) and (101) surfaces, where formation of oxygen vacancies is energetically more favorable. Furthermore, we present a vigorous, systematic screening of water incorporation onto the studied surfaces. We observe that the greatest stabilization of the surfaces is achieved when a part of the adsorbed water molecules is dissociated. Nevertheless, the importance of water dissociation for achieving the greatest stabilization is high for the less stable (011) and (101) surfaces, while completely hydrated (111) surface is stabilized equally regardless of the water dissociation state. Analysis of the constructed phase diagrams reveals that the (111) surface remains preferably clean and the (011) and (101) surfaces have dissociated water at low coverage under the reactive conditions of T = 600-900 K and p(H 2 O) < 1 bar. Upon temperature decrease and/or pressure increase, all studied surfaces gradually uptake water until fully hydrated. All in all, our findings complement and broaden the existing picture of the structure and stability of the monoclinic zirconia surfaces under the pre-treatment and/or reaction conditions, enabling rationalization of the potential roles of zirconia as a heterogeneous support and a catalyst component.

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Intrinsic point-defect equilibria in tetragonal ZrO2: Density functional theory analysis with finite-temperature effects

Cited by 80 publications

References 71 publications

Oxygen self-diffusion mechanisms in monoclinic ZrO2 revealed and quantified by density functional theory, random walk analysis, and kinetic Monte Carlo calculations

Oxygen self-diffusion mechanisms in monoclinic ZrO2 revealed and quantified by density functional theory, random walk analysis, and kinetic Monte Carlo calculations

Vacancies and defect levels in III–V semiconductors

Understanding Structure and Stability of Monoclinic Zirconia Surfaces from First-Principles Calculations

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