University of Oulu

Tyunina, M., & Savinov, M. (2020). Charge transport in epitaxial barium titanate films. Physical Review B, 101(9).

Charge transport in epitaxial barium titanate films

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Author: Tyunina, M.1,2; Savinov, M.2
Organizations: 1Microelectronics Research Unit, Faculty of Information Technology and Electrical Engineering, University of Oulu, P. O. Box 4500, FI-90014 Oulu, Finland
2Institute of Physics of the Czech Academy of Sciences, Na Slovance 2, 18221 Prague, Czech Republic
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.4 MB)
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Language: English
Published: American Physical Society, 2020
Publish Date: 2020-06-10


The electrical conductivity of epitaxial BaTiO₃ films was studied by small-signal impedance spectroscopy at temperatures of 10–720 K using Pt-BaTiO₃ — SrRuO₃ capacitors. The ∼150-nm-thick BaTiO₃ films possessed different lattice strains and degrees of oxygen deficiency. A crossover between the low-temperature hopping of small polarons and the high-temperature semiconductor- to metal-type behavior was demonstrated in all films. It was suggested that the small electron polarons originate from self-trapping at Ti in the stoichiometric tensile-strained film and from trapping at Ti next to the oxygen vacancy in the oxygen-deficient films. The conduction-band transport was ascribed to the thermally activated release of the trapped electrons. It was pointed out that the electronic release can mimic the motion of oxygen vacancies, which are actually immobile.

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Series: Physical review. B
ISSN: 2469-9950
ISSN-E: 2469-9969
ISSN-L: 2469-9950
Volume: 101
Issue: 9
Article number: 094106
DOI: 10.1103/PhysRevB.101.094106
Type of Publication: A1 Journal article – refereed
Field of Science: 114 Physical sciences
Funding: The authors acknowledge support from the Czech Science Foundation (Grant No. 19-09671S) and the European Structural and Investment Funds and the Ministry of Education, Youth and Sports of the Czech Republic through Programme “Research, Development and Education” (Project No. SOLID21-CZ.02.1.01/0.0/0.0/16_019/0000760). The authors are grateful to T. Kocourek for sample preparation and to J. Peräntie for structural analysis.
Copyright information: © 2020 American Physical Society. The Definitive Version of Record can be found online at: This article has been self-archived with the kind permission of the publisher.