Disentangling the role of small polarons and oxygen vacancies in 
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Sun, Lu; Huang, Xiaowei; Wang, Ligen; Janotti, Anderson

doi:10.1103/physrevb.95.245101

Cited by 75 publications

(43 citation statements)

References 71 publications

(151 reference statements)

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“…Hybrid functionals constitute a valid alternative to DFT+U, at the price of a higher computational cost, especially in the plane-waves. Among all hybrid functionals, the screened-exchange HSE06 functional is the most used to describe bulk CeO 2 and Ce 2 O 3 (Hay et al, 2006 ; Da Silva et al, 2007 ; Ganduglia-Pirovano et al, 2007 ; Du et al, 2018 ), oxygen vacancies at surfaces (Nolan, 2010 , 2011 ; Han et al, 2016 ), polarons (Sun et al, 2017 ) and dopants (Shi et al, 2016 ). Other non-screened functionals, such as B3LYP and B3PW91 were employed successfully to calculate the optical properties of bulk CeO 2 (El Khalifi et al, 2016 ).…”

Section: Atomistic Modeling Methods Of Doped Ceriamentioning

confidence: 99%

Rare Earth Doped Ceria: The Complex Connection Between Structure and Properties

et al. 2018

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The need for high efficiency energy production, conversion, storage and transport is serving as a robust guide for the development of new materials. Materials with physical-chemical properties matching specific functions in devices are produced by suitably tuning the crystallographic- defect- and micro-structure of the involved phases. In this review, we discuss the case of Rare Earth doped Ceria. Due to their high oxygen diffusion coefficient at temperatures higher than ~500°C, they are very promising materials for several applications such as electrolytes for Solid Oxide Fuel and Electrolytic Cells (SOFC and SOEC, respectively). Defects are integral part of the conduction process, hence of the final application. As the fluorite structure of ceria is capable of accommodating a high concentration of lattice defects, the characterization and comprehension of such complex and highly defective materials involve expertise spanning from computational chemistry, physical chemistry, catalysis, electrochemistry, microscopy, spectroscopy, and crystallography. Results coming from different experimental and computational techniques will be reviewed, showing that structure determination (at different scale length) plays a pivotal role bridging theoretical calculation and physical properties of these complex materials.

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Section: Atomistic Modeling Methods Of Doped Ceriamentioning

confidence: 99%

Rare Earth Doped Ceria: The Complex Connection Between Structure and Properties

et al. 2018

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“…We performed non-spin polarized calculations for these systems. The optimized structure parameters are listed in Table 1, together with the experimental and other theoretical values [14,[20][21][22][23][24][25]…”

Section: Methodsmentioning

confidence: 99%

Influence of Mixed Valence on the Formation of Oxygen Vacancy in Cerium Oxides

et al. 2019

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Ceria is one of the most important functional rare-earth oxides with wide industrial applications. Its amazing oxygen storage/release capacity is attributed to cerium’s flexible valence conversion between 4+ and 3+. However, there still exists some debate on whether the valence conversion is due to the Ce-4f electron localization-delocalization transition or the character of Ce–O covalent bonds. In this work, a mixed valence model was established and the formation energies of oxygen vacancies and electronic charges were obtained by density functional theory calculations. Our results show that the formation energy of oxygen vacancy is affected by the valence state of its neighboring Ce atom and two oxygen vacancies around a Ce4+ in CeO2 have a similar effect to a Ce3+. The electronic charge difference between Ce3+ and Ce4+ is only about 0.4e. Therefore, we argue that the valence conversion should be understood according to the adjustment of the ratio of covalent bond to ionic bond. We propose that the formation energy of oxygen vacancy be used as a descriptor to determine the valence state of Ce in cerium oxides.

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“…22 Later on, an explanation, based on semi-empirical quantum chemistry modeling, was put forth to explain the observed green luminescence. 23 Recently, improved calculations for the behavior of holes in oxides, based on the hybridfunctional density-functional theory (DFT), were introduced and applied to various metal oxides, [24][25][26][27] including the perovskite SrTiO 3 . 13,28 It was found that a hole in SrTiO 3 tends to be self-trapped, localizing on one oxygen atom.…”

Section: Introductionmentioning

confidence: 99%

Self-trapped holes in BaTiO3

Traiwattanapong

Janotti

Umezawa

et al. 2018

Journal of Applied Physics

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The behavior of holes in the valence band of BaTiO 3 is investigated using hybrid densityfunctional calculations. We find that holes tend to self-trap, localizing on individual O atoms and causing local lattice distortions, forming small hole-polarons. This takes place even in the absence of intrinsic defects or impurities. The self-trapped hole (STH) is more energetically favorable than the delocalized hole in the valence band. The calculated emission peak energy corresponding to the recombination of a conduction band electron with a STH can explain the observed photoluminescence at low temperatures. The stability of the STH, its migration barrier, and the related emission peak are then compared to those of SrTiO 3 .

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Disentangling the role of small polarons and oxygen vacancies in CeO2

Cited by 75 publications

References 71 publications

Rare Earth Doped Ceria: The Complex Connection Between Structure and Properties

Rare Earth Doped Ceria: The Complex Connection Between Structure and Properties

Influence of Mixed Valence on the Formation of Oxygen Vacancy in Cerium Oxides

Self-trapped holes in BaTiO3

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