Room-temperature soft mode and ferroelectric like polarization in SrTiO3 ultrathin films: Infrared and ab initio study

Abstract Due to the remarkable possibilities of epitaxially growing strontium titanate (SrTiO3 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 i...

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Autores principales:	Wei-wei Peng, Robert Tétot, Gang Niu, Emilie Amzallag, Bertrand Vilquin, Jean-Blaise Brubach, Pascale Roy
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2017
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/16e5cdaade794fe5ad654badc71eba52
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spelling	oai:doaj.org-article:16e5cdaade794fe5ad654badc71eba522021-12-02T12:32:59ZRoom-temperature soft mode and ferroelectric like polarization in SrTiO3 ultrathin films: Infrared and ab initio study10.1038/s41598-017-02113-42045-2322https://doaj.org/article/16e5cdaade794fe5ad654badc71eba522017-05-01T00:00:00Zhttps://doi.org/10.1038/s41598-017-02113-4https://doaj.org/toc/2045-2322Abstract Due to the remarkable possibilities of epitaxially growing strontium titanate (SrTiO3 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.Wei-wei PengRobert TétotGang NiuEmilie AmzallagBertrand VilquinJean-Blaise BrubachPascale RoyNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 7, Iss 1, Pp 1-11 (2017)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Wei-wei Peng Robert Tétot Gang Niu Emilie Amzallag Bertrand Vilquin Jean-Blaise Brubach Pascale Roy Room-temperature soft mode and ferroelectric like polarization in SrTiO3 ultrathin films: Infrared and ab initio study
description	Abstract Due to the remarkable possibilities of epitaxially growing strontium titanate (SrTiO3 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.
format	article
author	Wei-wei Peng Robert Tétot Gang Niu Emilie Amzallag Bertrand Vilquin Jean-Blaise Brubach Pascale Roy
author_facet	Wei-wei Peng Robert Tétot Gang Niu Emilie Amzallag Bertrand Vilquin Jean-Blaise Brubach Pascale Roy
author_sort	Wei-wei Peng
title	Room-temperature soft mode and ferroelectric like polarization in SrTiO3 ultrathin films: Infrared and ab initio study
title_short	Room-temperature soft mode and ferroelectric like polarization in SrTiO3 ultrathin films: Infrared and ab initio study
title_full	Room-temperature soft mode and ferroelectric like polarization in SrTiO3 ultrathin films: Infrared and ab initio study
title_fullStr	Room-temperature soft mode and ferroelectric like polarization in SrTiO3 ultrathin films: Infrared and ab initio study
title_full_unstemmed	Room-temperature soft mode and ferroelectric like polarization in SrTiO3 ultrathin films: Infrared and ab initio study
title_sort	room-temperature soft mode and ferroelectric like polarization in srtio3 ultrathin films: infrared and ab initio study
publisher	Nature Portfolio
publishDate	2017
url	https://doaj.org/article/16e5cdaade794fe5ad654badc71eba52
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Room-temperature soft mode and ferroelectric like polarization in SrTiO3 ultrathin films: Infrared and ab initio study

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