Defect-driven flexochemical coupling in thin ferroelectric films

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F18%3A10387961" target="_blank" >RIV/00216208:11320/18:10387961 - isvavai.cz</a>

Result on the web

<a href="https://doi.org/10.1103/PhysRevB.97.024102" target="_blank" >https://doi.org/10.1103/PhysRevB.97.024102</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1103/PhysRevB.97.024102" target="_blank" >10.1103/PhysRevB.97.024102</a>

Result language

angličtina

Original language name

Defect-driven flexochemical coupling in thin ferroelectric films

Original language description

Using the Landau-Ginzburg-Devonshire theory, we considered the impact of the flexoelectrochemical coupling on the size effects in polar properties and phase transitions of thin ferroelectric films with a layer of elastic defects. We investigated a typical case, when defects fill a thin layer below the top film surface with a constant concentration creating an additional gradient of elastic fields. The defective surface of the film is not covered with an electrode, but instead with an ultrathin layer of ambient screening charges, characterized by a surface screening length. Obtained results revealed an unexpectedly strong effect of the joint action of Vegard stresses and flexoelectric effect (shortly flexochemical coupling) on the ferroelectric transition temperature, distribution of the spontaneous polarization and elastic fields, domain wall structure and period in thin PbTiO3 films containing a layer of elastic defects. A nontrivial result is the persistence of ferroelectricity at film thicknesses below 4 nm, temperatures lower than 350 K, and relatively high surface screening length (TILDE OPERATOR+D910.1 nm). The origin of this phenomenon is the flexoelectric coupling leading to the rebuilding of the domain structure in the film (namely the cross-over from c-domain stripes to a-type closure domains) when its thickness decreases below 4 nm. The ferroelectricity persistence is facilitated by negative Vegard effect. For positive Vegard effect, thicker films exhibit the appearance of pronounced maxima on the thickness dependence of the transition temperature, whose position and height can be controlled by the defect type and concentration. The revealed features may have important implications for miniaturization of ferroelectric-based devices.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10302 - Condensed matter physics (including formerly solid state physics, supercond.)

Project

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Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2018

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Physical Review B

ISSN

2469-9950

e-ISSN

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Volume of the periodical

97

Issue of the periodical within the volume

2

Country of publishing house

US - UNITED STATES

Number of pages

17

Pages from-to

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UT code for WoS article

000419320300002

EID of the result in the Scopus database

2-s2.0-85040626948