Lattice dynamics of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">BaTiO</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mo>,</mml:mo></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">PbTiO</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>, and<mml:math

Ghosez, Philippe; Cockayne, Eric; Waghmare, Umesh V.; Rabe, Karin M.

doi:10.1103/physrevb.60.836

Cited by 449 publications

(197 citation statements)

References 40 publications

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“…α and β correspond components of the basis vector having labels of x, y or z which define the tensor element. The bulk high-frequency (optical) susceptibility χ ∞ for PbTiO 3 is 8.24 and, therefore, negligible in relation to the static component [40]. We find that both the c b → bc d and bc d → abc d transitions are accompanied by large dielectric response.…”

Section: Dielectric Responsementioning

confidence: 70%

Novel high-temperature ferroelectric domain morphology in PbTiO₃ ultrathin films

Chapman

Kimmel

Duffy

2017

Phys. Chem. Chem. Phys.

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Exotic domain morphologies in ferroic materials are an exciting avenue for the development of novel nanoelectronics. In this work we have used large scale molecular dynamics to construct a strain-temperature phase diagram of the domain morphology of PbTiO3 ultrathin films. Sampling a wide interval of strain values over a temperature range up to the Curie temperature Tc, we found that epitaxial strain induces the formation of a variety of closure-and in-plane domain morphologies. The local strain and ferroelectric-antiferrodistortive coupling at the film surface vary for the strain mediated transition sequence and this could offer a route for experimental observation of the morphologies. Remarkably, we identify a new nanobubble domain morphology that is stable in the high-temperature regime for compressively strained PbTiO3. We demonstrate that the formation mechanism of the nanobubble domains morphology is related to the wandering of flux closure domain walls, which we characterise using the hypertoroidal moment. These results provide insight into the local behaviour and dynamics of ferroelectric domains in ultrathin films to open up potential applications for bubble domains in new technologies and pathways to control and exploit novel phenomena in dimensionally constrained materials.

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Section: Dielectric Responsementioning

confidence: 70%

Novel high-temperature ferroelectric domain morphology in PbTiO₃ ultrathin films

Chapman

Kimmel

Duffy

2017

Phys. Chem. Chem. Phys.

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“…This directional long-ranged interaction was also predicted and considered as a main reason for the ferroelectric behaviour in perovskite BaTiO 3 and PbTiO 3 (ref. 29). We used a one-dimensional (1D) lattice chain model to explicitly show that the long-ranged interaction causes the softening of the TO mode (see Supplementary Note 5 for details).…”

Section: Resultsmentioning

confidence: 99%

Resonant bonding leads to low lattice thermal conductivity

et al. 2014

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Understanding the lattice dynamics and low thermal conductivities of IV-VI, V 2 -VI 3 and V materials is critical to the development of better thermoelectric and phase-change materials. Here we provide a link between chemical bonding and low thermal conductivity. Our first-principles calculations reveal that long-ranged interaction along the /100S direction of the rocksalt structure exist in lead chalcogenides, SnTe, Bi 2 Te 3 , Bi and Sb due to the resonant bonding that is common to all of them. This long-ranged interaction in lead chalcogenides and SnTe cause optical phonon softening, strong anharmonic scattering and large phase space for three-phonon scattering processes, which explain why rocksalt IV-VI compounds have much lower thermal conductivities than zincblende III-V compounds. The new insights on the relationship between resonant bonding and low thermal conductivity will help in the development of better thermoelectric and phase change materials.

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“…By this TO-to-TA transformation, the TA mode picks up soft Ti-O vibrations, leading to lower energy than the TO mode. Because the TO mode in Pm3m is quite anisotropic (18), the TA mode in I-43m is very anisotropic due to this TO-to-TA transformation. Thus, it is the anisotropic soft TA mode that leads to diffuse scattering in BaTO 3 .…”

Section: Resultsmentioning

confidence: 99%

“…These calculations also showed large volume dependence of the soft-mode potential surface and revealed the expected increase in total energies for the R, O, T, and C phases of BaTiO 3 . Further phonon analysis (17,18) on BaTiO 3 revealed two-dimensional character in the Brillouin zone, which corresponds to chains oriented along ͗100͘ directions of displaced Ti atoms. Such character had been found in KNbO 3 (19), a material with the same phase diagram as BaTiO 3 .…”

mentioning

confidence: 98%

The ferroelectric and cubic phases in BaTiO ₃ ferroelectrics are also antiferroelectric

Zhang

Çağın

Goddard

2006

Proc. Natl. Acad. Sci. U.S.A.

133

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Using quantum mechanics (QM, Density Functional Theory) we show that all four phases of barium titanate (BaTiO 3) have local Ti distortions toward ͗111͘ (an octahedral face). The stable rhombohedral phase has all distortions in phase (ferroelectric, FE), whereas higher temperature phases have antiferroelectric coupling (AFE) in one, two, or three dimensions (orthorhombic, tetragonal, cubic). This FE-AFE model from QM explains such puzzling aspects of these systems as the allowed Raman excitation observed for the cubic phase, the distortions toward ͗111͘ observed in the cubic phase using x-ray fine structure, the small transition entropies, the heavily damped soft phonon modes, and the strong diffuse x-ray scattering in all but the rhombohedral phase. In addition, we expect to see additional weak Bragg peaks at the face centers of the reciprocal lattice for the cubic phase. Similar FE-AFE descriptions are expected to occur for other FE materials. Accounting for this FE-AFE nature of these phases is expected to be important in accurately simulating the domain wall structures, energetics, and dynamics, which in turn may lead to the design of improved materials.barium titanate ͉ phase transition F erroelectric (FE) materials have broad applications in transducers, actuators, capacitors, and memories. Particularly well studied is BaTiO 3 , which has rhombohedral (R), orthorhombic (O), tetragonal (T), and cubic (C) phases. However, the microscopic nature of the phases and transitions in BaTiO 3 remains uncertain. A popular model in history is the displacive model (1, 2), in which the equilibrium position of each Ti atom is in the middle of the oxygen octahedron for C, but displaced microscopically in the ͗111͘, ͗011͘, or ͗001͘ macroscopic polarization directions for the R, O, and T ferroelectric phases, respectively. However, this displacive model Y Predicts that first-order Raman excitation should vanish in the cubic phase due to the microscopic inversion symmetry, contradicting experiments (3). Y Contradicts the x-ray fine structure (XAFS) experiments (4) that show that the Ti atoms are displaced along various of the eight possible ͗111͘ directions in all phases. Y Does not explain the heavily damped but nonzero frequency for the soft modes at the C to T transition observed by infrared reflectivity (IR) experiments (5). Y Does not explain the strong diffuse x-ray scattering observed in all but the rhombohedral phase.To explain these failures of the displacive model, a spontaneous symmetry breaking has been hypothesized to occur in these systems (6). Thus Berserker (7), Comes et al. (8) and Chaves et al. (9) introduced the order-disorder eight-site model (8OD), in which all Ti atoms are microscopically located in one of eight potential minima along the ͗111͘ directions for all crystal phases. As in the displacive model, 8OD assumes that the low temperature R phase has all Ti atoms distorted in the same direction. As temperature increases, 8OD assumes disorder in the polarization along one or more crystal directions...

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Lattice dynamics ofBaTiO3,PbTiO3, and

Cited by 449 publications

References 40 publications

Novel high-temperature ferroelectric domain morphology in PbTiO₃ ultrathin films

Novel high-temperature ferroelectric domain morphology in PbTiO₃ ultrathin films

Resonant bonding leads to low lattice thermal conductivity

The ferroelectric and cubic phases in BaTiO ₃ ferroelectrics are also antiferroelectric

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Lattice dynamics ofBaTiO3,PbTiO3, and

Cited by 449 publications

References 40 publications

Novel high-temperature ferroelectric domain morphology in PbTiO3 ultrathin films

Novel high-temperature ferroelectric domain morphology in PbTiO3 ultrathin films

Resonant bonding leads to low lattice thermal conductivity

The ferroelectric and cubic phases in BaTiO 3 ferroelectrics are also antiferroelectric

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Product

Resources

About

Novel high-temperature ferroelectric domain morphology in PbTiO₃ ultrathin films

Novel high-temperature ferroelectric domain morphology in PbTiO₃ ultrathin films

The ferroelectric and cubic phases in BaTiO ₃ ferroelectrics are also antiferroelectric