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Room-temperature soft mode and ferroelectric like polarization in SrTiO(3) ultrathin films: Infrared and ab initio study

Due to the remarkable possibilities of epitaxially growing strontium titanate (SrTiO(3) or STO) on silicon, this oxide is widely used as a buffer layer for integrating other perovskite oxides which allows for the development of various functional electronic devices on silicon. Moreover, STO is known...

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Autores principales: Peng, Wei-wei, Tétot, Robert, Niu, Gang, Amzallag, Emilie, Vilquin, Bertrand, Brubach, Jean-Blaise, Roy, Pascale
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5438411/
https://www.ncbi.nlm.nih.gov/pubmed/28526857
http://dx.doi.org/10.1038/s41598-017-02113-4
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author Peng, Wei-wei
Tétot, Robert
Niu, Gang
Amzallag, Emilie
Vilquin, Bertrand
Brubach, Jean-Blaise
Roy, Pascale
author_facet Peng, Wei-wei
Tétot, Robert
Niu, Gang
Amzallag, Emilie
Vilquin, Bertrand
Brubach, Jean-Blaise
Roy, Pascale
author_sort Peng, Wei-wei
collection PubMed
description Due to the remarkable possibilities of epitaxially growing strontium titanate (SrTiO(3) or STO) on silicon, this oxide is widely used as a buffer layer for integrating other perovskite oxides which allows for the development of various functional electronic devices on silicon. Moreover, STO is known to be an incipient ferroelectric in bulk but may become ferroelectric when in the form of strained ultrathin films. Given the importance of the potential applications for electronics if this property is demonstrated, we performed a spectroscopic study of STO on Si(001) templates coupling experimental and ab initio investigations. We selected six samples of ultrathin films: three strained samples (of thickness 4, 9 and 48 nm) and three relaxed samples (of equivalent thickness). Their infrared spectra show that both the mechanical stress and the thickness play major roles: higher energy modes evolve as soft modes in thinner strained films. In order to support these observations, the dynamical ab initio calculations allowed deriving the conditions for STO films to become ferroelectric at room temperature as shown by the development of a soft mode and the divergence of the in-plane dielectric constant.
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spelling pubmed-54384112017-05-22 Room-temperature soft mode and ferroelectric like polarization in SrTiO(3) ultrathin films: Infrared and ab initio study Peng, Wei-wei Tétot, Robert Niu, Gang Amzallag, Emilie Vilquin, Bertrand Brubach, Jean-Blaise Roy, Pascale Sci Rep Article Due to the remarkable possibilities of epitaxially growing strontium titanate (SrTiO(3) or STO) on silicon, this oxide is widely used as a buffer layer for integrating other perovskite oxides which allows for the development of various functional electronic devices on silicon. Moreover, STO is known to be an incipient ferroelectric in bulk but may become ferroelectric when in the form of strained ultrathin films. Given the importance of the potential applications for electronics if this property is demonstrated, we performed a spectroscopic study of STO on Si(001) templates coupling experimental and ab initio investigations. We selected six samples of ultrathin films: three strained samples (of thickness 4, 9 and 48 nm) and three relaxed samples (of equivalent thickness). Their infrared spectra show that both the mechanical stress and the thickness play major roles: higher energy modes evolve as soft modes in thinner strained films. In order to support these observations, the dynamical ab initio calculations allowed deriving the conditions for STO films to become ferroelectric at room temperature as shown by the development of a soft mode and the divergence of the in-plane dielectric constant. Nature Publishing Group UK 2017-05-19 /pmc/articles/PMC5438411/ /pubmed/28526857 http://dx.doi.org/10.1038/s41598-017-02113-4 Text en © The Author(s) 2017 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
spellingShingle Article
Peng, Wei-wei
Tétot, Robert
Niu, Gang
Amzallag, Emilie
Vilquin, Bertrand
Brubach, Jean-Blaise
Roy, Pascale
Room-temperature soft mode and ferroelectric like polarization in SrTiO(3) ultrathin films: Infrared and ab initio study
title Room-temperature soft mode and ferroelectric like polarization in SrTiO(3) ultrathin films: Infrared and ab initio study
title_full Room-temperature soft mode and ferroelectric like polarization in SrTiO(3) ultrathin films: Infrared and ab initio study
title_fullStr Room-temperature soft mode and ferroelectric like polarization in SrTiO(3) ultrathin films: Infrared and ab initio study
title_full_unstemmed Room-temperature soft mode and ferroelectric like polarization in SrTiO(3) ultrathin films: Infrared and ab initio study
title_short Room-temperature soft mode and ferroelectric like polarization in SrTiO(3) ultrathin films: Infrared and ab initio study
title_sort room-temperature soft mode and ferroelectric like polarization in srtio(3) ultrathin films: infrared and ab initio study
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5438411/
https://www.ncbi.nlm.nih.gov/pubmed/28526857
http://dx.doi.org/10.1038/s41598-017-02113-4
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