1. Interplay between Ca- and Ti-driven ferroelectric distortions in (Ba, Ca)TiO 3 solid solutions from first-principles calculations
- Author
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Andres Cano, Danila Amoroso, Philippe Ghosez, Université de Liège, Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Théorie de la Matière Condensée (TMC ), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and D.A. is grateful to S. Picozzi (CNR-SPIN) for the provided time needed for writing this paper and to B. Dkhil (Centrale-Supléc) for enlightening discussions. Ph.G. acknowledges the support of the F.R.S-FNRS Hit4Fit project. This work was supported by the European project EJD-FunMat 2015 and program H2020-MSCA-ITN-2014 under Grant Agreement No. 641640. Calculations have been performed on the Céci facilities funded by F.R.S-FNRS (Grant No. 2.5020.1) and on the Tier-1 supercomputer of the Fédération Wallonie-Bruxelles funded by the Walloon Region (Grant No. 1117545).
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010302 applied physics ,Steric effects ,[PHYS]Physics [physics] ,Phase boundary ,Materials science ,Physics and Astronomy (miscellaneous) ,02 engineering and technology ,[CHIM.MATE]Chemical Sciences/Material chemistry ,Partial substitution ,021001 nanoscience & nanotechnology ,01 natural sciences ,Ferroelectricity ,Piezoelectricity ,Chemical physics ,0103 physical sciences ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,[PHYS.COND]Physics [physics]/Condensed Matter [cond-mat] ,0210 nano-technology ,Polarization (electrochemistry) ,Solid solution ,Perovskite (structure) - Abstract
(Ba,Ca)(Ti,Zr)O3 solid solutions are promising lead-free piezoelectrics near their polymorphic phase boundary, which is believed to be linked to the interplay between B-site driven ferroelectricity and A-site driven ferroelectricity. Focusing on (Ba,Ca)TiO3, we support this picture from first-principles calculations. In particular, we show how steric effects related to the partial substitution of Ba by Ca largely enhance the Ca-driven ferroelectricity, already virtually allowed in the parent CaTiO3. The emergent interplay between the Ca-driven and Ti-driven mechanisms lowers the energy barrier between different polar states, which eventually results in a quasi-isotropic polarization under substitution of a small concentration of Ba by Ca. A sizeable enhancement of the piezoelectric response directly results from these features.(Ba,Ca)(Ti,Zr)O3 solid solutions are promising lead-free piezoelectrics near their polymorphic phase boundary, which is believed to be linked to the interplay between B-site driven ferroelectricity and A-site driven ferroelectricity. Focusing on (Ba,Ca)TiO3, we support this picture from first-principles calculations. In particular, we show how steric effects related to the partial substitution of Ba by Ca largely enhance the Ca-driven ferroelectricity, already virtually allowed in the parent CaTiO3. The emergent interplay between the Ca-driven and Ti-driven mechanisms lowers the energy barrier between different polar states, which eventually results in a quasi-isotropic polarization under substitution of a small concentration of Ba by Ca. A sizeable enhancement of the piezoelectric response directly results from these features.
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