Influence of oxygen partial pressure on SrTiO<sub>3</sub>bulk crystal growth from non-stoichiometric melts

Guguschev, Christo; Kok, Dirk J.; Galazka, Zbigniew; Klimm, D.; Uecker, R.; Bertram, R.; Naumann, M.; Juda, U.; Kwasniewski, Albert; Bickermann, Matthias

doi:10.1039/c5ce00095e

Cited by 12 publications

(27 citation statements)

References 29 publications

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“…The surface oxygen vacancies will be filled and Sr will move towards the surface, eventually forming an SrO terminated surface or even SrO nanocrystals [39,40]. It should be noted that the reoxidation depends subtly on the chemical composition of the material, and it has been reported that specially prepared crystals can remain reduced, even after high temperature oxidation [41]. As extended defects such as dislocations and antiphase boundaries could provide easy diffusion paths for Sr, the stoichiometry and crystallographic structure of the dislocations themselves might also be altered [42,43].…”

Section: Discussionmentioning

confidence: 99%

Is Reduced Strontium Titanate a Semiconductor or a Metal?

et al. 2021

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In recent decades, the behavior of SrTiO3 upon annealing in reducing conditions has been under intense academic scrutiny. Classically, its conductivity can be described using point defect chemistry and predicting n-type or p-type semiconducting behavior depending on oxygen activity. In contrast, many examples of metallic behavior induced by thermal reduction have recently appeared in the literature, challenging this established understanding. In this study, we aim to resolve this contradiction by demonstrating that an initially insulating, as-received SrTiO3 single crystal can indeed be reduced to a metallic state, and is even stable against room temperature reoxidation. However, once the sample has been oxidized at a high temperature, subsequent reduction can no longer be used to induce metallic behavior, but semiconducting behavior in agreement with the predictions of point defect chemistry is observed. Our results indicate that the dislocation-rich surface layer plays a decisive role and that its local chemical composition can be changed depending on annealing conditions. This reveals that the prediction of the macroscopic electronic properties of SrTiO3 is a highly complex task, and not only the current temperature and oxygen activity but also the redox history play an important role.

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Section: Discussionmentioning

confidence: 99%

Is Reduced Strontium Titanate a Semiconductor or a Metal?

et al. 2021

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“…Third, the existence of Ti Sr antisites has been experimentally observed with scanning transmission electron microscopy (STEM) in heteroepitaxial SrTiO 3 thin films, 7 suggesting that they can be present in SrTiO 3 in large concentrations. Finally, SrTiO 3 tends to be oxygen deficient 43 -hence the presence of a high concentration of O vacancies is natural. Theoretical calculations also predict that forming of a Ti Sr -V O pair is energetically favorable 5,6 .…”

Section: Defect Identitiesmentioning

confidence: 99%

TiSr antisite: An abundant point defect in SrTiO3

Karjalainen

Prozheeva

Makkonen

et al. 2020

Journal of Applied Physics

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We present a systematic study of the positron lifetime as a function of measurement temperature in SrTiO 3 single crystals grown in different conditions and by different synthesis methods. We combine our experimental results with state-of-the-art theoretical calculations of positron annihilation parameters. We find that the essentially omnipresent 180 − 190 ps lifetime component is most likely the Ti Sr antisite defect, possibly coupled with one or more oxygen vacancies, supporting the importance of the Ti Sr antisite related defects in SrTiO 3. 1

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“…Recently we demonstrated that large diameter (~30 mm) bulk crystals can be grown by high temperature top-seeded solution growth (TSSG) using nonstoichiometric TiO 2 -enriched melts and temperatures below 1800 °C. 20 Their EPD values were typically in the range between 2 × 10 4 and 2 × 10 5 cm −2 . Large areas of the crystals (in the cm range) were subgrain free and typical rocking curve FWHM values of 25 arcsec were determined.…”

Section: Introductionmentioning

confidence: 99%

Growth of SrTiO₃bulk single crystals using edge-defined film-fed growth and the Czochralski methods

et al. 2015

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Influence of oxygen partial pressure on SrTiO₃bulk crystal growth from non-stoichiometric melts

Cited by 12 publications

References 29 publications

Is Reduced Strontium Titanate a Semiconductor or a Metal?

Is Reduced Strontium Titanate a Semiconductor or a Metal?

TiSr antisite: An abundant point defect in SrTiO3

Growth of SrTiO₃bulk single crystals using edge-defined film-fed growth and the Czochralski methods

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Influence of oxygen partial pressure on SrTiO3bulk crystal growth from non-stoichiometric melts

Cited by 12 publications

References 29 publications

Is Reduced Strontium Titanate a Semiconductor or a Metal?

Is Reduced Strontium Titanate a Semiconductor or a Metal?

TiSr antisite: An abundant point defect in SrTiO3

Growth of SrTiO3bulk single crystals using edge-defined film-fed growth and the Czochralski methods

Contact Info

Product

Resources

About

Influence of oxygen partial pressure on SrTiO₃bulk crystal growth from non-stoichiometric melts

Growth of SrTiO₃bulk single crystals using edge-defined film-fed growth and the Czochralski methods