Single impurities in insulators: <i>Ab initio</i>study of Fe-doped<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">SrTiO</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

Ėvarestov, R. A.; Piskunov, Sergei; Kotomin, E. A.; Börstel, G.

doi:10.1103/physrevb.67.064101

Cited by 74 publications

(54 citation statements)

References 41 publications

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“…These two models have both similarities and discrepancies [15,16]. The similarity is that in both models not a standard primitive unit cell but an extended unit cell is used.…”

Section: Models and Computational Methodsmentioning

confidence: 94%

First‐principles periodic and semiempirical cyclic cluster calculations for single oxygen vacancies in crystalline Al₂O₃

Janetzko

Ėvarestov

Bredow³

et al. 2004

Physica Status Solidi (b)

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Single neutral and positively charged oxygen vacancies (F and F þ centers) in a-Al 2 O 3 are investigated using the supercell model (SCM) at the Hartree-Fock (HF) and density functional theory (DFT) level and the cyclic cluster model (CCM) implemented in the semiempirical MSINDO method. Results of supercell and cyclic cluster calculations for the cohesive energy of the perfect Al 2 O 3 crystal are compared with the experimental value for the heat of atomization. The defect formation energy of the unrelaxed F center is calculated with the SCM. The CCM is used to calculate the defect formation energy of the F and the F þ centers. Relaxation effects for the nearest neighbors (NN) and the nextnearest neighbors (NNN) of the F and F þ centers are investigated. The obtained values are compared to other theoretical literature data.

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“…These two models have both similarities and discrepancies [15,16]. The similarity is that in both models not a standard primitive unit cell but an extended unit cell is used.…”

Section: Models and Computational Methodsmentioning

confidence: 94%

First‐principles periodic and semiempirical cyclic cluster calculations for single oxygen vacancies in crystalline Al₂O₃

Janetzko

Ėvarestov

Bredow³

et al. 2004

Physica Status Solidi (b)

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“…13,19 This is also in agreement with a recent study on Fe impurity in SrTiO 3 suggesting that the interaction of periodically repeated defects can be quite considerable even for supercells containing 160 atoms. 43 The corresponding local geometry has been determined by total energy minimization with respect to the coordinates of atoms lying in spheres of increasing radius surrounding the vacancy or all atoms in the supercell. Since the cubic phase is relevant at room temperature, we will consider only this phase, which is also easier computationally.…”

Section: Computational Detailsmentioning

confidence: 99%

First-principles calculations of the atomic and electronic structure ofFcenters in the bulk and on the (001) surface ofSrTiO3

et al. 2006

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The atomic and electronic structure, formation energy, and the energy barriers for migration have been calculated for the neutral O vacancy point defect ͑F center͒ in cubic SrTiO 3 employing various implementations of density functional theory ͑DFT͒. Both bulk and TiO 2 -terminated ͑001͒ surface F centers have been considered. Supercells of different shapes containing up to 320 atoms have been employed. The limit of an isolated single oxygen vacancy in the bulk corresponds to a 270-atom supercell, in contrast to commonly used supercells containing ϳ40-80 atoms. Calculations carried out with the hybrid B3PW functional show that the F center level approaches the conduction band bottom to within ϳ0.5 eV, as the supercell size increases up to 320 atoms. The analysis of the electronic density maps indicates, however, that this remains a small-radius center with the two electrons left by the missing O ion being redistributed mainly between the vacancy and the 3d͑z 2 ͒ atomic orbitals of the two nearest Ti ions. As for the dynamical properties, the calculated migration energy barrier in the low oxygen depletion regime is predicted to be 0.4 eV. In contrast, the surface F center exhibits a more delocalized character, which leads to significantly reduced ionization and migration energies. Results obtained are compared with available experimental data.

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“…A recent study on a Fe impurity in SrTiO 3 has shown that defectdefect interactions can be quite considerable even for supercells containing 160 atoms, in particular at the DFT level. 39 In our models the distance between two vacancies along the z axis is 7.86 Å and 15.72 Å, respectively, for 40-and 80-atoms supercells. Going from the small to the large cell we do not observe major changes in the defect electronic structure ͑atomic charges, defect bandwidth, etc.͒.…”

Section: B Periodic Calculationsmentioning

confidence: 99%

Electronic structure of a neutral oxygen vacancy inSrTiO3

et al. 2003

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The electronic structure of an isolated oxygen vacancy in SrTiO 3 has been investigated with a variety of ab initio quantum mechanical approaches. In particular we compared pure density functional theory ͑DFT͒ approaches with the Hartree-Fock method, and with hybrid methods where the exchange term is treated in a mixed way. Both local cluster models and periodic calculations with large supercells containing up to 80 atoms have been performed. Both diamagnetic ͑singlet state͒ and paramagnetic ͑triplet state͒ solutions have been considered. We found that the formation of an O vacancy is accompanied by the transfer of two electrons to the 3d(z 2 ) orbitals of the two Ti atoms along the Ti-Vac-Ti axis. The two electrons are spin coupled and the ground state is diamagnetic. New states associated with the defect center appear in the gap just below the conduction band edge. The formation energy computed with respect to an isolated oxygen atom in the triplet state is 9.4 eV.

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Single impurities in insulators: Ab initiostudy of Fe-dopedSrTiO3

Cited by 74 publications

References 41 publications

First‐principles periodic and semiempirical cyclic cluster calculations for single oxygen vacancies in crystalline Al₂O₃

First‐principles periodic and semiempirical cyclic cluster calculations for single oxygen vacancies in crystalline Al₂O₃

First-principles calculations of the atomic and electronic structure ofFcenters in the bulk and on the (001) surface ofSrTiO3

Electronic structure of a neutral oxygen vacancy inSrTiO3

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Single impurities in insulators: Ab initiostudy of Fe-dopedSrTiO3

Cited by 74 publications

References 41 publications

First‐principles periodic and semiempirical cyclic cluster calculations for single oxygen vacancies in crystalline Al2O3

First‐principles periodic and semiempirical cyclic cluster calculations for single oxygen vacancies in crystalline Al2O3

First-principles calculations of the atomic and electronic structure ofFcenters in the bulk and on the (001) surface ofSrTiO3

Electronic structure of a neutral oxygen vacancy inSrTiO3

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First‐principles periodic and semiempirical cyclic cluster calculations for single oxygen vacancies in crystalline Al₂O₃

First‐principles periodic and semiempirical cyclic cluster calculations for single oxygen vacancies in crystalline Al₂O₃