Electronic structure of a neutral oxygen vacancy in<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>

Ricci, Davide; Bano, Giuseppe; Pacchioni, Gianfranco; Illas, Francesc

doi:10.1103/physrevb.68.224105

Cited by 120 publications

(103 citation statements)

References 45 publications

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“…Because they are tightly bound, they are ineffective in producing superconductivity. On the other hand, cluster calculations in SrTiO 3 [21][22][23] show that in this ternary perovskite there is a delicate balance between the electron pair's being localized around an oxygen vacancy and being delocalized throughout the cluster. There is even circumstantial evidence that such O vacancies may be essential for superconductivity found in SrTiO 3 [24].…”

Section: )Negative-u Centersmentioning

confidence: 96%

Enhanced superconductivity in Sr2CuO4−v

Geballe

Marezio

2009

Physica C: Superconductivity

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A critical review of previous investigations of the superconductivity with enhanced T c ~ 95K found in Sr 2 CuO 4-v shows that new physics occurs in a highly overdoped region of the cuprate phase diagram. Moreover, evidence is adduced from the literature that 30% of the oxygen sites in the CuO 2 layers are vacant, a conclusion which is at odds with the universally made assumption that superconductivity originates in stoichiometric CuO 2 layers. While further research is needed in order to identify the pairing mechanism(s) responsible for the enhanced T c , we suggest possible candidates. General ConsiderationsLiu et al. [1] and Yang et al. [2] have reopened the intriguing question concerning the origin of superconductivity in the cuprate superconductor Sr 2 CuO 3+d . This material had been synthesized at very high pressures in the presence of a strong oxidizing agent by several groups starting with the initial discovery of superconductivity by Hiroi et. al. [3], and followed by a series of careful experiments initiated by Han et al [4], and Laffez et al [5]. But those measurements were soon suspect due to the possibility of contamination by the oxidizing agent employed. As noted below the method employed [1] made three major improvements in the synthesis : 1) alleged impurity contamination was disproved, 2) the need for long range oxygen diffusion was removed, and 3) the synthesis provided a good estimate of oxygen concentration.Although the material is conventionally designated Sr 2 CuO 3+d we prefer to use the equivalent formula Sr 2 CuO 4-v because these superconductors have the same K 2 NiF 4 structure as the La 2 CuO 4 ["214"] cuprate family in which high temperature superconductivity was first

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Section: )Negative-u Centersmentioning

confidence: 96%

Enhanced superconductivity in Sr2CuO4−v

Geballe

Marezio

2009

Physica C: Superconductivity

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“…These are placed around the center of the O-vacancy, similar to the bulk STO with point defects 37 .…”

Section: A Vacancy Stripe Configurationsmentioning

confidence: 99%

“…Moreover, the STM experiments and DFT+U studies suggest the possibility that oxygen vacancies form pieces of linear chains, which appear to be more energetically favourable 34 as compared to the isolated vacancies [35][36][37] .…”

Section: Introductionmentioning

confidence: 99%

Oxygen vacancies at titanate interfaces: Two-dimensional magnetism and orbital reconstruction

et al. 2012

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We show that oxygen vacancies at titanate interfaces induce a complex multiorbital reconstruction which involves a lowering of the local symmetry and an inversion of t2g and eg orbitals resulting in the occupation of the eg orbitals of Ti atoms neighboring the O vacancy. The orbital reconstruction depends strongly on the clustering of O vacancies and can be accompanied by a magnetic splitting between the local eg orbitals with lobes directed towards the vacancy and interface dxy orbitals. The reconstruction generates a two-dimensional interface magnetic state not observed in bulk SrTiO3. Using generalized gradient approximation (LSDA) with intra-atomic Coulomb repulsion (GGA+U), we find that this magnetic state is common for titanate surfaces and interfaces.

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“…47 However, using a 135 atoms and 320 atoms simulation cell we find that the singlet state (zero residual spin) is the ground state. 48 Fig. 2 shows the spin density profile for an oxygen vacancy in a 40 atoms supercell under neutral charge conditions.…”

Section: A Oxygen Vacancymentioning

confidence: 99%

Method for defect stability diagram fromab initiocalculations: A case study of SrTiO3

2012

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Point defects play a dominant role in determining the wide spectrum of electronic and physical properties of semiconducting materials that have vast technological applications. Using ab-initio simulations, a method to calculate equilibrium defect concentrations, Fermi energy and defect stability diagrams as functions of external parameters, such as temperature and pressure, is presented. Using SrTiO3 as a representative material, we report our analysis of the stability of oxygen vacancies and interstitials, in their different charge states, as a function of temperature, oxygen partial pressure and Fermi energy of the system. Further, by analyzing the defect chemistry at experimentally relevant temperatures, we find that at low oxygen partial pressure, neutral oxygen vacancies are most dominant and at intermediate and high oxygen partial pressure, doubly charged oxygen vacancies defects are dominant.

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Electronic structure of a neutral oxygen vacancy inSrTiO3

Cited by 120 publications

References 45 publications

Enhanced superconductivity in Sr2CuO4−v

Enhanced superconductivity in Sr2CuO4−v

Oxygen vacancies at titanate interfaces: Two-dimensional magnetism and orbital reconstruction

Method for defect stability diagram fromab initiocalculations: A case study of SrTiO3

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