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Tsuzuki, A.; Kato, Kazumi; Kusumoto, Keiji; Torii, Yasuyoshi

doi:10.1023/a:1018561611459

Cited by 10 publications

(4 citation statements)

References 9 publications

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“…For example, the c-lattice constant, the unit cell volume V, and c/a increase by off-stoichiometry. [66][67][68][69][70][71] This problem is severe for Si and Ge substrates because an insufficient oxidizing environment is used. These elongations of the c-lattice constant are due to a pure chemical origin and unrelated with ferroelectricity or the depolarization field because they occur in many nonferroelectric metal oxides.…”

Section: Tetragonal Batio 3 Under External Strainmentioning

confidence: 99%

“…These elongations of the c-lattice constant are due to a pure chemical origin and unrelated with ferroelectricity or the depolarization field because they occur in many nonferroelectric metal oxides. [66][67][68][69][70][71] On the other hand, the increase of c/a is reduced by dislocations, which tends to occur for large strain. 36,72,73 These data are removed or remarked in Figs.…”

Section: Tetragonal Batio 3 Under External Strainmentioning

confidence: 99%

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Calculation of strained BaTiO3 with different exchange correlation functionals examined with criterion by Ginzburg-Landau theory, uncovering expressions by crystallographic parameters

Watanabe

2018

The Journal of Chemical Physics

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In the calculations of tetragonal BaTiO 3 , some exchange-correlation (XC) energy functionals such as local density approximation (LDA) have shown good agreement with experiments at room temperature (RT), e.g., spontaneous polarization (P S), and superiority compared with other XC functionals. This is due to the error compensation of the RT effect and, hence, will be ineffective in the heavily strained case such as domain boundaries. Here, ferroelectrics under large strain at RT are approximated as those at 0 K because the strain effect surpasses the RT effects. To find effective XC energy functionals for strained BaTiO 3 , we propose a new comparison, i.e., a criterion. This criterion is the properties at 0 K given by the Ginzburg-Landau (GL) theory because GL theory is a thermodynamic description of experiments working under the same symmetry-constraints as ab initio calculations. With this criterion, we examine LDA, generalized gradient approximations (GGA), meta-GGA, meta-GGA + local correlation potential (U), and hybrid functionals, which reveals the high accuracy of some XC functionals superior to XC functionals that have been regarded as accurate. This result is examined directly by the calculations of homogenously strained tetragonal BaTiO 3 , confirming the validity of the new criterion. In addition, the data points of theoretical P S vs. certain crystallographic parameters calculated with different XC functionals are found to lie on a single curve, despite their wide variations. Regarding these theoretical data points as corresponding to the experimental results, analytical expressions of the local P S using crystallographic parameters are uncovered. These expressions show the primary origin of BaTiO 3 ferroelectricity as oxygen displacements. Elastic compliance and electrostrictive coefficients are estimated. For the comparison of strained results, we show that the effective critical temperature T C under strain <0.01 is >1000 K from an approximate method combining ab initio results with GL theory. In addition, in a definite manner, the present results show much more enhanced ferroelectricity at large strain than the previous reports.

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Section: Tetragonal Batio 3 Under External Strainmentioning

confidence: 99%

Section: Tetragonal Batio 3 Under External Strainmentioning

confidence: 99%

Calculation of strained BaTiO3 with different exchange correlation functionals examined with criterion by Ginzburg-Landau theory, uncovering expressions by crystallographic parameters

Watanabe

2018

The Journal of Chemical Physics

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“…This is because SrTiO 3 -1 is a Sr-rich material with a Sr : Ti atomic ratio of B1.03 : 1 (1 : 1 for SrTiO 3 -2), and the excess Sr 2+ ions (with a larger ionic radius than Ti 4+ ) could be substituted for Ti 4+ ions in SrTiO 3 -1. 8 The slight variation in the microstructure of the material caused by this ''selfsubstitution'' effect was also detected using X-ray photoelectron spectroscopy (XPS, Fig. S2 in ESI †).…”

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confidence: 92%

Nanoporous Sr-rich strontium titanate: a stable and superior photocatalyst for H2 evolution

et al. 2013

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“…This is probably a consequence of their structural instability. 7. Summary Approaching to defect chemistry of electronic perovskite ceramics using high-resolution transmission electron microscopy and first-principles (ab-initio) pseudopotential total energy calculations effectively clarified new type of defect structures and its special features.…”

Section: Ruddlesden-popper Planar Defects In A-site-excessmentioning

confidence: 99%

High-Resolution Transmission Electron Microscopy and Computer Simulation of Defect Structures in Electronic Perovskite Ceramics.

Fujimoto

Suzuki

2001

J. Ceram. Soc. Japan

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Defect chemistry of electronic perovskite ceramics was quite advanced by recent studies using high-resolu tion transmission electron microscopy (TEM) and computer simulation techniques. Selective site occupation of alkali-earth metal, Ca at Ruddlesden-Popper (RP) faults, causing a break of conduction pathway within a framework of corner-sharing TiO6 octahedra and improved leakage current properties, were unquestionable clarified in A-site-excess SrTiO3. Existence of meta-stable RP faults in BaTiO3 processed under thermody namically non-equilibrium condition was first empirically and then theoretically proved. Crystallographic shear (CS) structure TiO2 double layer and BaO double layer were first observed and precisely characterized in perovskite ceramics. The obtained new information about defect structure can trigger new ideas about standing reliabilityissues and should open a challenge in atomic design, based upon computer structural energy calculation in electronic perovskite materials.

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Cited by 10 publications

References 9 publications

Calculation of strained BaTiO3 with different exchange correlation functionals examined with criterion by Ginzburg-Landau theory, uncovering expressions by crystallographic parameters

Calculation of strained BaTiO3 with different exchange correlation functionals examined with criterion by Ginzburg-Landau theory, uncovering expressions by crystallographic parameters

Nanoporous Sr-rich strontium titanate: a stable and superior photocatalyst for H2 evolution

High-Resolution Transmission Electron Microscopy and Computer Simulation of Defect Structures in Electronic Perovskite Ceramics.

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