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Pan Q, Gu ZX, Zhou RJ, Feng ZJ, Xiong YA, Sha TT, You YM, Xiong RG. The past 10 years of molecular ferroelectrics: structures, design, and properties. Chem Soc Rev 2024; 53:5781-5861. [PMID: 38690681 DOI: 10.1039/d3cs00262d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
Ferroelectricity, which has diverse important applications such as memory elements, capacitors, and sensors, was first discovered in a molecular compound, Rochelle salt, in 1920 by Valasek. Owing to their superiorities of lightweight, biocompatibility, structural tunability, mechanical flexibility, etc., the past decade has witnessed the renaissance of molecular ferroelectrics as promising complementary materials to commercial inorganic ferroelectrics. Thus, on the 100th anniversary of ferroelectricity, it is an opportune time to look into the future, specifically into how to push the boundaries of material design in molecular ferroelectric systems and finally overcome the hurdles to their commercialization. Herein, we present a comprehensive and accessible review of the appealing development of molecular ferroelectrics over the past 10 years, with an emphasis on their structural diversity, chemical design, exceptional properties, and potential applications. We believe that it will inspire intense, combined research efforts to enrich the family of high-performance molecular ferroelectrics and attract widespread interest from physicists and chemists to better understand the structure-function relationships governing improved applied functional device engineering.
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Affiliation(s)
- Qiang Pan
- Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing 211189, P. R. China.
| | - Zhu-Xiao Gu
- Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing 211189, P. R. China.
- State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210008, P. R. China.
| | - Ru-Jie Zhou
- Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing 211189, P. R. China.
| | - Zi-Jie Feng
- Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing 211189, P. R. China.
| | - Yu-An Xiong
- Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing 211189, P. R. China.
| | - Tai-Ting Sha
- Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing 211189, P. R. China.
| | - Yu-Meng You
- Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing 211189, P. R. China.
| | - Ren-Gen Xiong
- Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing 211189, P. R. China.
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Topological Excitations in Neutral–Ionic Transition Systems. Symmetry (Basel) 2022. [DOI: 10.3390/sym14050925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/10/2022] Open
Abstract
The existence and physical properties of topological excitations in ferroelectrics, especially mobile topological boundaries in one dimension, are of profound interest. Notably, topological excitations emerging in association with the neutral–ionic (NI) phase transition are theoretically suggested to carry fractional charges and cause anomalous charge transport. In recent years, we experimentally demonstrated mobile topological excitations in a quasi-one-dimensional (1D) ferroelectric, tetrathiafulvalene-p-chloranil [TTF-CA; TTF (C6H4S4) and CA (C6Cl4O2)], which shows the NI transition, using NMR, NQR, and electrical resistivity measurements. Thermally activated topological excitations carry charges and spins in the NI crossover region and in the ionic phase with a dimer liquid. Moreover, free solitons show a binding transition upon a space-inversion symmetry-breaking ferroelectric order. In this article, we review the recent progress in the study of mobile topological excitations emerging in TTF-CA, along with earlier reports that intensively studied these phenomena, aiming to provide the foundations of the physics of electrical conductivity and magnetism carried by topological excitations in the 1D ferroelectric.
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Guérin L, Yoshida T, Zatterin E, Simonov A, Chernyshov D, Iguchi H, Toudic B, Takaishi S, Yamashita M. Elucidating 2D Charge-Density-Wave atomic structure in an MX-chain by the 3D-ΔPair Distribution Function method. Chemphyschem 2022; 23:e202100857. [PMID: 35083834 DOI: 10.1002/cphc.202100857] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 01/26/2022] [Indexed: 11/07/2022]
Abstract
Many solids, particularly low-dimensional systems, exhibit charge density waves (CDWs). In one dimension, charge density waves are well understood, but in two dimensions, their structure and their origin are difficult to reveal. Here, the 2D Charge-Density-Wave atomic structure and stabilization mechanism in the bromide-bridged Pd compound [Pd(cptn) 2 Br]Br 2 (cptn = 1 R ,2 R -diaminocyclopentane) is investigated by means of single-crystal X-ray diffraction employing the 3D-ΔPair Distribution Function (3D-ΔPDF) method. Analysis of the diffuse scattering using 3D-ΔPDF shows that a 2D-CDW is stabilized by a hydrogen-bonding network between Br - counteranion and the amine (NH 2 ) group of the cptn in-plane ligand, and that 3D ordering is prevented due to a weak plane to plane correlation. We extract the effective displacements of the atoms describing the atomic structure quantitatively and discuss the stabilization mechanism of the 2D-CDW. Our study provides a method to identify and measure the key interaction responsible for the dimensionality and stability of the CDW that can help further progress of rational design.
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Affiliation(s)
- Laurent Guérin
- Univ Rennes, CNRS, PR (Institut de Physique de Rennes) - UMR 6251, 35000, Rennes, France
| | - Takefumi Yoshida
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-Ku, Sendai, 980-8578, Japan
| | - Edoardo Zatterin
- Univ Rennes, CNRS, PR (Institut de Physique de Rennes) - UMR 6251, 35000, Rennes, France
- ESRF-The European Synchrotron, BM31, 71 Avenue des Martyrs, Grenoble, 38000, France
| | - Arkadiy Simonov
- Univ Rennes, CNRS, PR (Institut de Physique de Rennes) - UMR 6251, 35000, Rennes, France
- Materials Department, ETH Zürich, Vladimir-Prelog-Weg 1-5/10, 8093, Zürich, Switzerland
| | - Dmitry Chernyshov
- Swiss-Norwegian BeamLines at the ESRF, 71 Avenue des Martyrs, Grenoble, 38000, France
| | - Hiroaki Iguchi
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-Ku, Sendai, 980-8578, Japan
| | - Bertrand Toudic
- Univ Rennes, CNRS, PR (Institut de Physique de Rennes) - UMR 6251, 35000, Rennes, France
| | - Shinya Takaishi
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-Ku, Sendai, 980-8578, Japan
| | - Masahiro Yamashita
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-Ku, Sendai, 980-8578, Japan
- School of Materials Science and Engineering, Nankai University, Tianjin, 300350, China
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Takehara R, Sunami K, Miyagawa K, Miyamoto T, Okamoto H, Horiuchi S, Kato R, Kanoda K. Topological charge transport by mobile dielectric-ferroelectric domain walls. SCIENCE ADVANCES 2019; 5:eaax8720. [PMID: 31763453 PMCID: PMC6858255 DOI: 10.1126/sciadv.aax8720] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 09/19/2019] [Indexed: 06/10/2023]
Abstract
The concept of topology has been widely applied in condensed matter physics, leading to the identification of peculiar electronic states on three-dimensional (3D) surfaces or 2D lines separating topologically distinctive regions. In the systems explored so far, the topological boundaries are built-in walls; thus, their motional degrees of freedom, which potentially bring about new paradigms, have been experimentally inaccessible. Here, working with a quasi-1D organic material with a charge-transfer instability, we show that mobile neutral-ionic (dielectric-ferroelectric) domain boundaries with topological charges carry strongly 1D-confined and anomalously large electrical conduction with an energy gap much smaller than the one-particle excitation gap. This consequence is further supported by nuclear magnetic resonance detection of spin solitons, which are required for steady current of topological charges. The present observation of topological charge transport may open a new channel for broad charge transport-related phenomena such as thermoelectric effects.
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Affiliation(s)
- R. Takehara
- Department of Applied Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - K. Sunami
- Department of Applied Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - K. Miyagawa
- Department of Applied Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - T. Miyamoto
- Department of Advanced Materials Science, University of Tokyo, Kashiwa, Chiba 277-8561, Japan
| | - H. Okamoto
- Department of Advanced Materials Science, University of Tokyo, Kashiwa, Chiba 277-8561, Japan
- AIST-UTokyo Advanced Operando–Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), Chiba 277-8568, Japan
| | - S. Horiuchi
- Flexible Electronics Research Center (FLEC), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8565, Japan
| | - R. Kato
- Condensed Molecular Materials Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - K. Kanoda
- Department of Applied Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
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Sunami K, Nishikawa T, Miyagawa K, Horiuchi S, Kato R, Miyamoto T, Okamoto H, Kanoda K. Evidence for solitonic spin excitations from a charge-lattice-coupled ferroelectric order. SCIENCE ADVANCES 2018; 4:eaau7725. [PMID: 30515457 PMCID: PMC6269158 DOI: 10.1126/sciadv.aau7725] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 10/30/2018] [Indexed: 06/09/2023]
Abstract
Topological defects have been explored in different fields ranging from condensed matter physics and particle physics to cosmology. In condensed matter, strong coupling between charge, spin, and lattice degrees of freedom brings about emergent excitations with topological characteristics at low energies. One-dimensional (1D) systems with degenerate dimerization patterns are typical stages for the generation of topological defects, dubbed "solitons"; for instance, charged solitons are responsible for high electrical conductivity in doped trans-polyacetylene. Here, we provide evidence based on a nuclear magnetic resonance (NMR) study for mobile spin solitons deconfined from a strongly charge-lattice-coupled spin-singlet ferroelectric order in a quasi-1D organic charge-transfer complex. The NMR spectral shift and relaxation rate associated with static and dynamic spin susceptibilities indicate that the ferroelectric order is violated by dilute solitonic spin excitations, which were further demonstrated to move diffusively by the frequency dependence of the relaxation rate. The traveling solitons revealed here may promise the emergence of anomalous electrical and thermal transport.
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Affiliation(s)
- K. Sunami
- Department of Applied Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - T. Nishikawa
- Department of Applied Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - K. Miyagawa
- Department of Applied Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - S. Horiuchi
- Flexible Electronics Research Center (FLEC), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8565, Japan
| | - R. Kato
- Condensed Molecular Materials Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - T. Miyamoto
- Department of Advanced Materials Science, University of Tokyo, Kashiwa, Chiba 277-8561, Japan
| | - H. Okamoto
- Department of Advanced Materials Science, University of Tokyo, Kashiwa, Chiba 277-8561, Japan
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of AIST, Chiba 277-8568, Japan
| | - K. Kanoda
- Department of Applied Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
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Back to the Structural and Dynamical Properties of Neutral-Ionic Phase Transitions. CRYSTALS 2017. [DOI: 10.3390/cryst7100285] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Chergui M, Collet E. Photoinduced Structural Dynamics of Molecular Systems Mapped by Time-Resolved X-ray Methods. Chem Rev 2017; 117:11025-11065. [DOI: 10.1021/acs.chemrev.6b00831] [Citation(s) in RCA: 150] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Majed Chergui
- Laboratoire
de Spectroscopie Ultrarapide (LSU), ISIC, and Lausanne Centre for
Ultrafast Science (LACUS), Faculté des Sciences de Base, Ecole Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
| | - Eric Collet
- Univ Rennes 1, CNRS, Institut de Physique de Rennes, UMR 6251, UBL, Rennes F-35042, France
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Phenomenology of the Neutral-Ionic Valence Instability in Mixed Stack Charge-Transfer Crystals. CRYSTALS 2017. [DOI: 10.3390/cryst7040108] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Morimoto T, Miyamoto T, Yamakawa H, Terashige T, Ono T, Kida N, Okamoto H. Terahertz-Field-Induced Large Macroscopic Polarization and Domain-Wall Dynamics in an Organic Molecular Dielectric. PHYSICAL REVIEW LETTERS 2017; 118:107602. [PMID: 28339244 DOI: 10.1103/physrevlett.118.107602] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Indexed: 05/24/2023]
Abstract
A rapid polarization control in paraelectric materials is important for an ultrafast optical switching useful in the future optical communication. In this study, we applied terahertz-pump second-harmonic-generation-probe and optical-reflectivity-probe spectroscopies to the paraelectric neutral phase of an organic molecular dielectric, tetrathiafulvalene-p-chloranil and revealed that a terahertz pulse with the electric-field amplitude of ∼400 kV/cm produces in the subpicosecond time scale a large macroscopic polarization whose magnitude reaches ∼20% of that in the ferroelectric ionic phase. Such a large polarization generation is attributed to the intermolecular charge transfers and breathing motions of domain walls between microscopic neutral and ionic domains induced by the terahertz electric field.
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Affiliation(s)
- T Morimoto
- Department of Advanced Materials Science, University of Tokyo, Kashiwa 5-1-5, Chiba 277-8561, Japan
| | - T Miyamoto
- Department of Advanced Materials Science, University of Tokyo, Kashiwa 5-1-5, Chiba 277-8561, Japan
| | - H Yamakawa
- Department of Advanced Materials Science, University of Tokyo, Kashiwa 5-1-5, Chiba 277-8561, Japan
| | - T Terashige
- Department of Advanced Materials Science, University of Tokyo, Kashiwa 5-1-5, Chiba 277-8561, Japan
| | - T Ono
- Department of Advanced Materials Science, University of Tokyo, Kashiwa 5-1-5, Chiba 277-8561, Japan
| | - N Kida
- Department of Advanced Materials Science, University of Tokyo, Kashiwa 5-1-5, Chiba 277-8561, Japan
| | - H Okamoto
- Department of Advanced Materials Science, University of Tokyo, Kashiwa 5-1-5, Chiba 277-8561, Japan
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Starodub VA, Starodub TN. Radical anion salts and charge transfer complexes based on tetracyanoquinodimethane and other strong π-electron acceptors. RUSSIAN CHEMICAL REVIEWS 2014. [DOI: 10.1070/rc2014v083n05abeh004299] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Hoshino M, Nozawa S, Sato T, Tomita A, Adachi SI, Koshihara SY. Time-resolved X-ray crystal structure analysis for elucidating the hidden ‘over-neutralized’ phase of TTF-CA. RSC Adv 2013. [DOI: 10.1039/c3ra42489h] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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Kobayashi K, Horiuchi S, Kumai R, Kagawa F, Murakami Y, Tokura Y. Electronic ferroelectricity in a molecular crystal with large polarization directing antiparallel to ionic displacement. PHYSICAL REVIEW LETTERS 2012; 108:237601. [PMID: 23003988 DOI: 10.1103/physrevlett.108.237601] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Indexed: 06/01/2023]
Abstract
Ferroelectric polarization of 6.3 μC cm(-2) is induced by the neutral-to-ionic transition, upon which nonpolar molecules of electron donor tetrathiafulvalene (TTF) and acceptor p-chloranil (CA) are incompletely ionized to ±0.60e and dimerized along the molecular stacking chain. We find that the ferroelectric properties are governed by intermolecular charge transfer rather than simple displacement of static point charge on molecules. The observed polarization and poling effect on the absolute structural configuration can be interpreted in terms of electronic ferroelectricity, which not only exhibits antiparallel polarity to the ionic displacement but also enhances the polarization more than 20 times that of the point-charge model.
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Affiliation(s)
- Kensuke Kobayashi
- Condensed Matter Research Center (CMRC) and Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, 305-0801, Japan.
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Guérin L, Hébert J, Buron-Le Cointe M, Adachi SI, Koshihara SY, Cailleau H, Collet E. Capturing one-dimensional precursors of a photoinduced transformation in a material. PHYSICAL REVIEW LETTERS 2010; 105:246101. [PMID: 21231536 DOI: 10.1103/physrevlett.105.246101] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Indexed: 05/29/2023]
Abstract
Achieving control of photoinduced phase transitions requires understanding how materials work during transformation induced by a laser pulse. Here we investigate the precursors of a photoinduced phase transition in the highly cooperative charge-transfer molecular crystal tetrathiafulvalene-p-chloranil and provide key insights. The photogeneration of one-dimensional nanoscale clusters was detected by time-resolved diffuse x-ray scattering with 50-ps time resolution. Such clustering of structurally relaxed electronic excitations is expected to be a common process in many materials presenting photoinduced transformations.
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Affiliation(s)
- Laurent Guérin
- JST, Exploratory Research for Advanced Technology, 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan
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Kagawa F, Horiuchi S, Matsui H, Kumai R, Onose Y, Hasegawa T, Tokura Y. Electric-field control of solitons in a ferroelectric organic charge-transfer salt. PHYSICAL REVIEW LETTERS 2010; 104:227602. [PMID: 20867204 DOI: 10.1103/physrevlett.104.227602] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Indexed: 05/29/2023]
Abstract
The role of solitons in transport, dielectric, and magnetic properties has been revealed for the quasi-one-dimensional organic charge-transfer salt, TTF-QBrCl3 [tetrathiafulvalene (TTF)-2-bromo-3,5,6-trichloro-p-benzoquinone (QBrCl3)]. The material was found to be ferroelectric and hence the solitons should be located at the boundary of the segments with opposite electric polarization. This feature enabled the electric-field control of soliton density and hence the clear-cut detection of soliton contributions. The gigantic dielectric response in the ferroelectric phase is ascribed to the dynamical bound and creeping motions of spinless solitons.
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Affiliation(s)
- F Kagawa
- Multiferroics Project, ERATO, Japan Science and Technology Agency, c/o Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan
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State of the art and opportunities in probing photoinduced phase transitions in molecular materials by conventional and picosecond X-ray diffraction. ACTA ACUST UNITED AC 2009. [DOI: 10.1524/zkri.2008.0027] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Abstract
The optical control of the macroscopic physical properties (magnetic, optical …) of a material by laser irradiation is gaining interest through the emerging field of photoinduced phase transitions. Light-induced changes of the macroscopic state of a material involves subtle coupling between the electronic and structural degrees of freedom, which are essential to stabilize the photo-excited state, different in nature from the stable state. Therefore the new experimental field of photocrystallography plays a key role. It goes far beyond simple structural analysis under laser excitation. By playing on different physical parameters and developing the techniques and analysis, one can investigate new out of equilibrium physics through light-driven cooperative dynamics and transformations in materials. This paper is reviewing different aspects of the use of photocrystallography to investigate the nature, the mechanisms and the dynamics of photoinduced phase transitions for photo-steady or long-lived states, as well as transformations driven by an ultra-short light pulse. We also give a brief overview on recent advances in time-resolved crystallography with 100 ps resolution.
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D'Avino G, Girlando A, Painelli A, Lemée-Cailleau MH, Soos ZG. Anomalous dispersion of optical phonons at the neutral-ionic transition: evidence from diffuse x-ray scattering. PHYSICAL REVIEW LETTERS 2007; 99:156407. [PMID: 17995198 DOI: 10.1103/physrevlett.99.156407] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2007] [Indexed: 05/25/2023]
Abstract
Diffuse x-ray data for mixed-stack organic charge-transfer crystals approaching the neutral-ionic phase transition can be quantitatively explained as due to the softening of the optical phonon branch. The interpretation is fully consistent with vibrational spectra, and underlines the importance of electron-phonon coupling in low-dimensional systems with delocalized electrons.
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Affiliation(s)
- Gabriele D'Avino
- Dipartimento di Chimica GIAF, Parma University, & INSTM UdR Parma, 43100 Parma, Italy
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