University of Oulu

Pacherova, O., Chvostova, D., Kocourek, T., Jelinek, M., Dejneka, A., Eliseev, E., Morozovska, A., Tyunina, M. (2018) Thermooptical evidence of carrier-stabilized ferroelectricity in ultrathin electrodeless films. Scientific Reports, 8 (1), 8497. doi:10.1038/s41598-018-26933-0

Thermooptical evidence of carrier-stabilized ferroelectricity in ultrathin electrodeless films

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Author: Pacherova, O.1; Chvostova, D.1; Kocourek, T.1;
Organizations: 1Institute of Physics of the Czech Academy of Sciences
2Institute of Problems for Material Sciences, NAS of Ukraine
3Institute of Physics, NAS of Ukraine
4Microelectronics Research Unit, Faculty of Information Technology and Electrical Engineering, University of Oulu
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.7 MB)
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Language: English
Published: Springer Nature,
Publish Date: 2018-08-21


Ferroelectric films may lose polarization as their thicknesses decrease to a few nanometers because of the depolarizing field that opposes the polarization therein. The depolarizing field is minimized when electrons or ions in the electrodes or the surface/interface layers screen the polarization charge or when peculiar domain configuration is formed. Here, we demonstrate ferroelectric phase transitions using thermooptical studies in ∼5-nm-thick epitaxial Pb0.5Sr0.5TiO3 films grown on different insulating substrates. By comparing theoretical modeling and experimental observations, we show that ferroelectricity is stabilized through redistribution of charge carriers (electrons or holes) inside ultrathin films. The related high-density of screening carriers is confined within a few-nanometers-thick layer in the vicinity of the insulator, thus resembling a two-dimensional carrier gas.

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Series: Scientific reports
ISSN: 2045-2322
ISSN-E: 2045-2322
ISSN-L: 2045-2322
Volume: 8
Issue: 1
Article number: 8497
DOI: 10.1038/s41598-018-26933-0
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
Funding: The authors acknowledge support from the Czech Science Foundation (Grants No. 15–15123 S and No. 15–13778S).
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