Giant LO-TO splittings in perovskite ferroelectrics

Zhong, W. L.; King-Smith, R. D.; Vanderbilt, David

doi:10.1103/physrevlett.72.3618

Cited by 908 publications

(729 citation statements)

References 14 publications

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“…Similar behavior has been observed in BiFeO 3 [28]. The high values of the BEC tensors in perovskite oxides indicate the presence of ferroelectricity [37]. In Fig.…”

Section: Resultssupporting

confidence: 65%

Electronic structure, ferroelectric properties, and phase stability of BiGaO3 under high pressure from first principles

Kaczkowski

2016

J Mater Sci

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High-pressure behavior of BiGaO 3 has been investigated from 0 to 20 GPa using density functional theory. It is found that BiGaO 3 undergoes a pressure-induced first-order phase transition from pyroxene (Pcca) to monoclinic (Cm) at 3.5 GPa, and then to rhombohedral (R3c) at 5.2 GPa, and finally to orthorhombic (Pnma) structure at 7.4 GPa. The first phase transition (Pcca ? Cm) agrees well with the experimental results. At 5.2 GPa the possible coexistence of three ferroelectric phases, i.e., monoclinic Cm, tetragonal P4mm, and rhombohedral R3c has been predicted. The calculated values of spontaneous polarization for these phases are of 124.87, 123.48, 88.75 lC/cm 2 for Cm, P4mm, and R3c, respectively.

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“…Similar behavior has been observed in BiFeO 3 [28]. The high values of the BEC tensors in perovskite oxides indicate the presence of ferroelectricity [37]. In Fig.…”

Section: Resultssupporting

confidence: 65%

Electronic structure, ferroelectric properties, and phase stability of BiGaO3 under high pressure from first principles

Kaczkowski

2016

J Mater Sci

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“…[68][69][70][71][72] Additionally, cross-gap mixing of cation (p) and anion (p) states is evident, which has been associated with elevated Born effective charges, giant splitting between longitudinal and transverse optical modes (LO/TO splitting), and polar instability in perovskite oxides. [73][74][75][76] Systems with these electronic features exhibit a strong electron-phonon coupling (and atomic displacement-polarization coupling), with implications for charge transport and defect tolerance. 14 Comparison with isostructural CsPbBr 3 and CsCaBr 3 allows us to examine the influence of the s 2 lone pair electrons on the electronic structure and lattice dynamics: Pb 2+ is predicted to have a lesser tendency for stereochemical activity due to greater relativistic The band structure of CsPbBr 3 is similar to that of CsSnBr 3 , but the competing effects of longer metal-Br bond length, reduced ionicity of metal-Br interaction, and stronger spinorbit coupling result in a wider bandgap and larger carrier effective masses at this level of theory.…”

Section: Ab Initio Studies Of Cubic Cssnbrmentioning

confidence: 99%

Dynamic Stereochemical Activity of the Sn²⁺ Lone Pair in Perovskite CsSnBr₃

et al. 2016

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Stable s 2 lone pair electrons on heavy main-group elements in their lower oxidation states drive a range of important phenomena, such as the emergence of polar ground states in some ferroic materials. Here we study the perovskite halide CsSnBr 3 as an embodiment of the broader materials class. We show that lone pair stereochemical activity due to the Sn s 2 lone pair causes a crystallographically hidden, locally distorted state to appear upon warming, a phenomenon previously referred to as emphanisis.The synchrotron X-ray pair distribution function acquired between 300 K and 420 K reveals emerging asymmetry in the nearest-neighbor Sn-Br correlations, consistent with dynamic Sn 2+ off-centering, despite there being no evidence of any deviation from the average cubic structure. Computation based on density functional theory supports the finding of a lattice instability associated with dynamic off-centering of Sn 2+ in its coordination environment. Photoluminescence measurements reveal an unusual blueshift with increasing temperature, closely linked to the structural evolution. At low temperatures, the structures reflect the influence of octahedral rotation. A continuous transition from an orthorhombic structure (P nma, no. 62) to a tetragonal structure (P 4/mbm, no. 127) is found around 250 K, with a final, first-order transformation at 286 K to the cubic structure (P m3m, no. 221).2

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“…The contribution of the depolarization field to the total energy is large enough to completely destabilize the bulk FE state. 15,16 Therefore, relaxing a polarized slab under the boundary condition of a vanishing external electric field will inevitably result in a paraelectric cubic structure.…”

Section: Electrical Boundary Conditionsmentioning

confidence: 99%

Ab initiostudy ofBaTiO3andPbTiO3surfaces in external ele

2001

Self Cite

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For the ferroelectric perovskite compounds BaTiO3 and PbTiO3, we have studied the effects of external electric fields on the structural properties of the (001) surfaces. The field-induced changes in the surface interlayer spacings and bucklings have been calculated using a first-principles ultrasoftpseudopotential approach, and the change of the polarization and the ferroelectric distortions in the surface layers have been obtained. The surfaces are represented by periodically repeated slabs, and an external dipole layer is included in the vacuum region of the supercells to control the electric field normal to the surfaces. The influence of the electrical boundary conditions on the ferroelectric properties of the slabs is discussed. In the case of a vanishing internal electric field, our study indicates that even very thin slabs can show a ferroelectric instability.

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Giant LO-TO splittings in perovskite ferroelectrics

Cited by 908 publications

References 14 publications

Electronic structure, ferroelectric properties, and phase stability of BiGaO3 under high pressure from first principles

Electronic structure, ferroelectric properties, and phase stability of BiGaO3 under high pressure from first principles

Dynamic Stereochemical Activity of the Sn²⁺ Lone Pair in Perovskite CsSnBr₃

Ab initiostudy ofBaTiO3andPbTiO3surfaces in external ele

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Giant LO-TO splittings in perovskite ferroelectrics

Cited by 908 publications

References 14 publications

Electronic structure, ferroelectric properties, and phase stability of BiGaO3 under high pressure from first principles

Electronic structure, ferroelectric properties, and phase stability of BiGaO3 under high pressure from first principles

Dynamic Stereochemical Activity of the Sn2+ Lone Pair in Perovskite CsSnBr3

Ab initiostudy ofBaTiO3andPbTiO3surfaces in external ele

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Dynamic Stereochemical Activity of the Sn²⁺ Lone Pair in Perovskite CsSnBr₃