First-principles study of intrinsic point defects in hexagonal barium titanate

Dawson, James A.; Harding, John H.; Chen, H.R.; Sinclair, Derek C.

doi:10.1063/1.4711099

Cited by 20 publications

(20 citation statements)

References 54 publications

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“…The experimental evidence that τ t and

⟨ τ ⟩

are around of one order of magnitude higher in Er‐doped BT with respect to the pure material is consistent with this trapping effect. On the other hand, the presence of complex defects formed by

{normalV}_{normalO}^{• •}

–

{normalV}_{Ba}^{''}

and

{normalV}_{normalO}^{• •}

–

{normalV}_{Ti}^{''''}

–

{normalV}_{normalO}^{• •}

suggests that these host metal vacancies form a valid trap for the mobile oxygen vacancies .

{normalV}_{Ti}^{''''}

binds preferentially to

{normalV}_{normalO}^{• •}

reducing the cohesive energy of the crystal ; this fact has been confirmed in this work by the high binding energy exhibited by this defect configuration.…”

Section: Resultssupporting

confidence: 73%

Can erbium dopant occupy both cation sites in cubic barium titanate via a mechanism different than self‐compensation?

Zulueta

Guerrero

Leyet

et al. 2014

Physica Status Solidi (b)

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The defect energetics for several dopant incorporation modes and the dielectric–electric properties in Er‐doped BaTiO3 were studied by numerical simulations and the dielectric modulus formalism. Two “mixed” incorporation modes, both compatible with the existence of oxygen vacancies, are proposed. Simulation results for the solution energies show that, despite self‐compensation is the most favourable mode, the mixed modes exhibit quite similar energies and, therefore, could be active under some conditions. The incorporation of Er3+ into the BaTiO3 lattice decreases the dc conductivities with respect to the undoped case at high temperatures. Molecular Dynamics calculations and experimental measurements about conducting properties of Er‐doped BaTiO3 allow one to calculate activation energies for ionic conductivity, which agree with data for oxygen migration. Experimental and Molecular Dynamics data are then correlated with the possible defect configurations. Scheme of the defect clusters corresponding to the proposed mixed incorporation mechanisms: (a) “Ti‐vac” and (b) “Ba‐vac”. Green, grey, blue, and red balls correspond, respectively, to Ba2+, Ti4+, Er3+, and O2− ions.

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“…The experimental evidence that τ t and

⟨ τ ⟩

are around of one order of magnitude higher in Er‐doped BT with respect to the pure material is consistent with this trapping effect. On the other hand, the presence of complex defects formed by

{normalV}_{normalO}^{• •}

–

{normalV}_{Ba}^{''}

and

{normalV}_{normalO}^{• •}

–

{normalV}_{Ti}^{''''}

–

{normalV}_{normalO}^{• •}

suggests that these host metal vacancies form a valid trap for the mobile oxygen vacancies .

{normalV}_{Ti}^{''''}

binds preferentially to

{normalV}_{normalO}^{• •}

reducing the cohesive energy of the crystal ; this fact has been confirmed in this work by the high binding energy exhibited by this defect configuration.…”

Section: Resultssupporting

confidence: 73%

Can erbium dopant occupy both cation sites in cubic barium titanate via a mechanism different than self‐compensation?

Zulueta

Guerrero

Leyet

et al. 2014

Physica Status Solidi (b)

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“…Despite the interest of these studies, it is evident that any detailed description of the defect energetics should take into account explicitly the electronic structure of the system. In this sense, DFT has been successfully employed to elucidate the defect structure of pure [13][14][15] and rare-earth doped barium titanate [16].…”

Section: Introductionmentioning

confidence: 99%

First-principles study of neutral defects in Fe-doped cubic barium titanate

Meléndez

Zulueta

Leyet

2015

Ceramics International

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“…Thus, divalent dopants (behaving as M 2+ ) have often been incorporated into both ATiO 3 perovskite structures to improve their thermoelectrical and conducting properties. The doping process depends on various factors such as the chemical environment where the dopant is incorporated in the ATiO 3 lattice structure, the tolerance factor as a function of the ionic radius of the dopant, and the oxygen partial pressure combined with electron doping [16][17][18][19][20]. Recently, the existence of two new incorporation mechanisms for rare-earth dopants was demonstrated on the basis of experimental investigations of Erdoped BaTiO 3 (BT) [21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Multisite occupation of divalent dopants in barium and strontium titanates

Zulueta

Nguyen

2018

Journal of Physics and Chemistry of Solids

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Based on recent experimental and theoretical proofs of calcium multisite occupation in barium titanate, we investigated a mixed incorporation mechanism for divalent dopants in barium and strontium titanates (BaTiO 3 and SrTiO 3 ). Our present theoretical results demonstrated the multisite occupation of divalent dopants in both perovskite structures. We determined the dependences of the solution, binding energies, and final solution energies with respect to the ionic radii of the dopants. Calculated results obtained based on classical simulations showed that the divalent dopants can occupy both A-and Ti-cation sites in ATiO 3 perovskite structures. Such a multisite occupation has direct implications for other experimental findings regarding BaTiO 3 , such as nonstabilization of the tetragonal phase, shifts in the Curie temperature, intensification of the diffuse phase transition, and shifts in the absorption of ultraviolet light to the visible range in photocatalytic applications related to solar cells for producing energy.

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First-principles study of intrinsic point defects in hexagonal barium titanate

Abstract: Density functional theory (DFT) calculations have been used to study the nature of intrinsic defects in the hexagonal polymorph of barium titanate. Defect formation energies are derived for multiple charge states and due consideration is given to finite-size effects (elastic and

Cited by 20 publications

References 54 publications

Can erbium dopant occupy both cation sites in cubic barium titanate via a mechanism different than self‐compensation?

Can erbium dopant occupy both cation sites in cubic barium titanate via a mechanism different than self‐compensation?

First-principles study of neutral defects in Fe-doped cubic barium titanate

Multisite occupation of divalent dopants in barium and strontium titanates

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