A Supramolecular Ferroelectric Realized by Collective Proton Transfer

Horiuchi, Sachio; Kumai, Reiji; Tokura, Y.

doi:10.1002/ange.200700407

Cited by 42 publications

(28 citation statements)

References 24 publications

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“…DFT calculations demonstrate the role of phonons and show that vibrational free-energy stabilisation, which plays a key role in the observed structural phase transitions, is more pronounced in the fully deuterated material and proportional to the mass of the molecule, that is, the level of deuteration. This is consistent with our experimental work, for which distinct crystallographic phase transitions parting the functionality in new organic ferroelectrics [10] and in the recently reported vapochromic metal-hydrazone complexes developed for chemical sensing applications. [11] Very little is known about the effect of isotopic substitution on proton migration in SSHBs.…”

Section: Introductionsupporting

confidence: 92%

Giant Deuteron Migration During the Isosymmetric Phase Transition in Deuterated 3,5‐Pyridinedicarboxylic Acid

Ford

Delamore

Evans

et al. 2011

Chemistry A European J

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Deuterated 3,5-pyridinedicarboxylic acid exhibits reversible temperature-induced deuteron migration of a magnitude unprecedented in this class of compounds. We used a combination of variable-temperature powder and single-crystal neutron diffraction and density functional theory (DFT)-based computational methods to elucidate the origin of this remarkable behaviour. Single-crystal neutron diffraction shows that between 15 and 300 K, the deuteron moves by 0.32(1) Å and the structure changes from a low-temperature N-D···O form to a high-temperature N···D-O form. Variable-temperature powder neutron-diffraction data, which was fitted by using parametric Rietveld refinement, show that this deuteron migration is due to an isosymmetric, first-order phase transition that occurs by growth of the daughter phase in the parent-phase matrix. Similar phase transitions are observed in two selectively deuterated forms of the material. DFT calculations demonstrate the role of phonons and show that vibrational free-energy stabilisation, which plays a key role in the observed structural phase transitions, is more pronounced in the fully deuterated material and proportional to the mass of the molecule, that is, the level of deuteration. This is consistent with our experimental work, for which distinct crystallographic phase transitions were clearly observed for the three deuterated systems, but not for the fully protonated material.

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Section: Introductionsupporting

confidence: 92%

Giant Deuteron Migration During the Isosymmetric Phase Transition in Deuterated 3,5‐Pyridinedicarboxylic Acid

Ford

Delamore

Evans

et al. 2011

Chemistry A European J

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“…Here, we briefly discuss the possible reason why such a ferroelectric multidomain state appears in as-grown crystals. Single crystals of [D-55DMBP][Dia] were prepared by recrystallization at room temperature [19], which is lower than Tc = 335 K.…”

Section: Ferroelectric Domain Imaging Using Emission Of Terahertz mentioning

confidence: 99%

“…Here, we propose a new method to visualize ferroelectric domains and DWs in the inside and surface regions of organic ferroelectrics and applied this method to an organic molecular crystal, 1:1 salt of 5,5'-dimethyl-2,2'-bipyridine (55DMBP) and deuterium iodanilic acid (D2ia) ([D-55DMBP][Dia]), which was recently found to be a room-temperature ferroelectric [19]. We show that terahertz wave is emitted by the irradiation of a femtosecond laser pulse and effective depth radiating the terahertz waves exhibits large polarization dependence.…”

Section: Introductionmentioning

confidence: 99%

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Terahertz Radiation Imaging of Ferroelectric Domain Topography in Room-Temperature Hydrogen-Bonded Supramolecular Ferroelectrics

et al. 2015

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Organic ferroelectrics with lightweight, flexible, low-cost, and environmentally benign characteristics are recently receiving great attention for new electric and optical devices. Since the propagation of ferroelectric domain walls and the subsequent reformation of ferroelectric domains are the basis for these devices, detection of the ferroelectric domain topology is crucial. Here, we demonstrate a new method to detect ferroelectric domains in inside and surface regions of organic ferroelectrics by mapping out two orthogonally polarized terahertz waves radiated from the crystal upon the irradiation of near-infrared femtosecond laser pulses. We used polarization dependence of the effective depths radiating the terahertz waves, which originate from the optical anisotropy in the terahertz frequency region. This allows us to distinguish ferroelectric domains in the inside and surface regions of the crystals. We applied this method to a room-temperature organic supramolecular ferroelectric crystal, 1:1 salt of 5,5'-dimethyl-2,2'-bipyridine and deuterated iodanilic acid. A single domain covering almost all the area of an as-grown crystal (600 m  800 m) is discerned in the inside region, while complicated multi-domain in size of 200 m is observed in the surface 2 region. By applying external electric field along the 2c-b axis (ferroelectric polarization direction), the polarization switching proceeds with successive propagations of uncharged (neutral) and quasi-one-dimensional 180 domain walls (DWs) along the b-axis ( 2c-b axis). This results in the formation of another uncharged and two-dimensional 180 DW parallel to the (100) plane, which covers all the area of the crystal. We discuss the usefulness of the present terahertz radiation imaging technique and ferroelectric DW dynamics in terms of anisotropic stacking of hydrogen-bonded chains. PACS 78.30.Jw, 77.80.-e, 42.30.-d, 42.65.Re DWs perpendicular to P. Since uncharged DWs are electrically stable (divP = 0), they are observed in various ferroelectrics [2]. On the other hand, charged DWs such as head-to-head (tail-to-tail) DWs have net bound charge (divP  0), which should be compensated by charged objects such as free carriers, defects, and impurities. Charged DWs frequently appear in as-grown crystals [7-10] and as-grown thin films [11-13].Therefore, real-space imaging of ferroelectric domain topology is not only indispensable to understand the nature of ferroelectricity but also crucial for the applications of ferroelectric materials.Recently, new series of room-temperature hydrogen-bonded ferroelectrics with large ferroelectric polarization have been developed in a family of low-dimensional

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“…Examples of antiferroelectric phases can also be seen in molecular crystals (2,6,27), organic-inorganic hybrid perovskites (28), and liquid crystals (4) such as benzimidazoles organic crystals (29). For a 1:1 adduct of iodanilic/chloranilic acid with 5,5 -dimethyl-2,2 -bipyridine (55DMBP), for example, ferroelectricity and antiferroelectricity emerge for iodanilic and chloranilic acids, respectively (11,30). It was also shown that the ferroelectric transition in the former case vanishes at high pressure, while another anomaly in dielectric permittivity remains.…”

mentioning

confidence: 99%

Self-organization into ferroelectric and antiferroelectric crystals via the interplay between particle shape and dipolar interaction

Takae

Tanaka

2018

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

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Ferroelectricity and antiferroelectricity are widely seen in various types of condensed matter and are of technological significance not only due to their electrical switchability but also due to intriguing cross-coupling effects such as electro-mechanical and electro-caloric effects. The control of the two types of dipolar order has practically been made by changing the ionic radius of a constituent atom or externally applying strain for inorganic crystals and by changing the shape of a molecule for organic crystals. However, the basic physical principle behind such controllability involving crystal-lattice organization is still unknown. On the basis of a physical picture that a competition of dipolar order with another type of order is essential to understand this phenomenon, here we develop a simple model system composed of spheroid-like particles with a permanent dipole, which may capture an essence of this important structural transition in organic systems. In this model, we reveal that energetic frustration between the two types of anisotropic interactions, dipolar and steric interactions, is a key to control not only the phase transition but also the coupling between polarization and strain. Our finding provides a fundamental physical principle for self-organization to a crystal with desired dipolar order and realization of large electro-mechanical effects.

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A Supramolecular Ferroelectric Realized by Collective Proton Transfer

Cited by 42 publications

References 24 publications

Giant Deuteron Migration During the Isosymmetric Phase Transition in Deuterated 3,5‐Pyridinedicarboxylic Acid

Giant Deuteron Migration During the Isosymmetric Phase Transition in Deuterated 3,5‐Pyridinedicarboxylic Acid

Terahertz Radiation Imaging of Ferroelectric Domain Topography in Room-Temperature Hydrogen-Bonded Supramolecular Ferroelectrics

Self-organization into ferroelectric and antiferroelectric crystals via the interplay between particle shape and dipolar interaction

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