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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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2
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Miyamoto T, Kondo A, Inaba T, Morimoto T, You S, Okamoto H. Terahertz radiation by quantum interference of excitons in a one-dimensional Mott insulator. Nat Commun 2023; 14:6229. [PMID: 37833316 PMCID: PMC10575914 DOI: 10.1038/s41467-023-41463-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 09/01/2023] [Indexed: 10/15/2023] Open
Abstract
Nearly monocyclic terahertz waves are used for investigating elementary excitations and for controlling electronic states in solids. They are usually generated via second-order optical nonlinearity by injecting a femtosecond laser pulse into a nonlinear optical crystal. In this framework, however, it is difficult to control phase and frequency of terahertz waves. Here, we show that in a one-dimensional Mott insulator of a nickel-bromine chain compound a terahertz wave is generated with high efficiency via strong electron modulations due to quantum interference between odd-parity and even-parity excitons produced by two-color femtosecond pulses. Using this method, one can control all of the phase, frequency, and amplitude of terahertz waves by adjusting the creation-time difference of two excitons with attosecond accuracy. This approach enables to evaluate the phase-relaxation time of excitons under strong electron correlations in Mott insulators. Moreover, phase- and frequency-controlled terahertz pulses are beneficial for coherent electronic-state controls with nearly monocyclic terahertz waves.
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Affiliation(s)
- Tatsuya Miyamoto
- Department of Advanced Materials Science, University of Tokyo, Chiba, 277-8561, Japan.
| | - Akihiro Kondo
- Department of Advanced Materials Science, University of Tokyo, Chiba, 277-8561, Japan
| | - Takeshi Inaba
- Department of Advanced Materials Science, University of Tokyo, Chiba, 277-8561, Japan
| | - Takeshi Morimoto
- Department of Advanced Materials Science, University of Tokyo, Chiba, 277-8561, Japan
| | - Shijia You
- Department of Advanced Materials Science, University of Tokyo, Chiba, 277-8561, Japan
| | - Hiroshi Okamoto
- Department of Advanced Materials Science, University of Tokyo, Chiba, 277-8561, Japan.
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3
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Brekhov K, Bilyk V, Ovchinnikov A, Chefonov O, Mukhortov V, Mishina E. Resonant Excitation of the Ferroelectric Soft Mode by a Narrow-Band THz Pulse. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:1961. [PMID: 37446477 DOI: 10.3390/nano13131961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 06/17/2023] [Accepted: 06/23/2023] [Indexed: 07/15/2023]
Abstract
This study investigates the impact of narrow-band terahertz pulses on the ferroelectric order parameter in Ba0.8Sr0.2TiO3 films on various substrates. THz radiation in the range of 1-2 THz with the pulse width of about 0.15 THz was separated from a broadband pulse with the interference technique. The 375 nm thick BST film on a MgO (001) substrate exhibits enhanced THz-induced second harmonic generation when excited by THz pulses with a central frequency of 1.6 THz, due to the resonant excitation of the soft phonon mode. Conversely, the BST film on a Si (001) substrate shows no enhancement, due to its polycrystalline state. The 800 nm thick BST film on a MgO (111) substrate demonstrates the maximum of a second harmonic generation signal when excited by THz pulses at 1.8 THz, which is close to the soft mode frequency for the (111) orientation. Notably, the frequency spectrum of the BST/MgO (111) film reveals peaks at both the fundamental and doubled frequencies, and their intensities depend, respectively, linearly and quadratically on the THz pulse electric field strength.
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Affiliation(s)
- Kirill Brekhov
- Department of Nanoelectronics, MIREA-Russian Technological University, Moscow 119454, Russia
| | - Vladislav Bilyk
- Institute for Molecules and Materials, Radboud University, 6525 AJ Nijmegen, The Netherlands
| | - Andrey Ovchinnikov
- Joint Institute for High Temperatures of Russian Academy of Sciences (JIHT), Moscow 125412, Russia
| | - Oleg Chefonov
- Joint Institute for High Temperatures of Russian Academy of Sciences (JIHT), Moscow 125412, Russia
| | - Vladimir Mukhortov
- Southern Scientific Center of Russian Academy of Sciences, Rostov-on-Don 344006, Russia
| | - Elena Mishina
- Department of Nanoelectronics, MIREA-Russian Technological University, Moscow 119454, Russia
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Yu H, Okimoto Y, Morita A, Shimanuki S, Takubo K, Ishikawa T, Koshihara SY, Minakami R, Itoh H, Iwai S, Ikeda N, Sakagami T, Nozaki M, Fujii T. Nonlinear Optical Properties in an Epitaxial YbFe 2O 4 Film Probed by Second Harmonic and Terahertz Generation. MATERIALS (BASEL, SWITZERLAND) 2023; 16:1989. [PMID: 36903104 PMCID: PMC10004718 DOI: 10.3390/ma16051989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 02/23/2023] [Accepted: 02/24/2023] [Indexed: 06/18/2023]
Abstract
An epitaxial film of YbFe2O4, a candidate for oxide electronic ferroelectrics, was fabricated on yttrium-stabilized zirconia (YSZ) substrate by magnetron sputtering technique. For the film, second harmonic generation (SHG), and a terahertz radiation signal were observed at room temperature, confirming a polar structure of the film. The azimuth angle dependence of SHG shows four leaves-like profiles and is almost identical to that in a bulk single crystal. Based on tensor analyses of the SHG profiles, we could reveal the polarization structure and the relationship between the film structure of YbFe2O4 and the crystal axes of the YSZ substrate. The observed terahertz pulse showed anisotropic polarization dependence consistent with the SHG measurement, and the intensity of the emitted terahertz pulse reached about 9.2% of that emitted from ZnTe, a typical nonlinear crystal, implying that YbFe2O4 can be applied as a terahertz wave generator in which the direction of the electric field can be easily switched.
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Affiliation(s)
- Hongwu Yu
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1, Meguro, Tokyo 152-8551, Japan
| | - Yoichi Okimoto
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1, Meguro, Tokyo 152-8551, Japan
| | - Atsuya Morita
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1, Meguro, Tokyo 152-8551, Japan
| | - Shuhei Shimanuki
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1, Meguro, Tokyo 152-8551, Japan
| | - Kou Takubo
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1, Meguro, Tokyo 152-8551, Japan
| | - Tadahiko Ishikawa
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1, Meguro, Tokyo 152-8551, Japan
| | - Shin-ya Koshihara
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1, Meguro, Tokyo 152-8551, Japan
| | - Ryusei Minakami
- Department of Physics, Tohoku University, Sendai 980-8578, Japan
| | - Hirotake Itoh
- Department of Physics, Tohoku University, Sendai 980-8578, Japan
| | - Shinichiro Iwai
- Department of Physics, Tohoku University, Sendai 980-8578, Japan
| | - Naoshi Ikeda
- Department of Physics, Okayama University, 3-1-1, Tsushimanaka, Okayama 700-8530, Japan
| | - Takumi Sakagami
- Department of Applied Chemistry, Okayama University, 3-1-1, Tsushimanaka, Okayama 700-8530, Japan
| | - Mayu Nozaki
- Department of Applied Chemistry, Okayama University, 3-1-1, Tsushimanaka, Okayama 700-8530, Japan
| | - Tatsuo Fujii
- Department of Applied Chemistry, Okayama University, 3-1-1, Tsushimanaka, Okayama 700-8530, Japan
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Shao C, Shi X, Wang J, Xu J, Huang H. Designing Ultrafast Cooling Rate for Room Temperature Electrocaloric Effects by Phase‐Field Simulations. ADVANCED THEORY AND SIMULATIONS 2022. [DOI: 10.1002/adts.202200406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Cancan Shao
- School of Materials Science and Engineering Beijing Institute of Technology Beijing 100081 China
- Advanced Research Institute of Multidisciplinary Science Beijing Institute of Technology Beijing 100081 China
| | - Xiaoming Shi
- School of Materials Science and Engineering Beijing Institute of Technology Beijing 100081 China
- Advanced Research Institute of Multidisciplinary Science Beijing Institute of Technology Beijing 100081 China
| | - Jing Wang
- School of Materials Science and Engineering Beijing Institute of Technology Beijing 100081 China
- Advanced Research Institute of Multidisciplinary Science Beijing Institute of Technology Beijing 100081 China
| | - Jiwen Xu
- Guangxi Key Laboratory of Information Materials Guilin University of Electronic Technology Guilin 541004 China
| | - Houbing Huang
- School of Materials Science and Engineering Beijing Institute of Technology Beijing 100081 China
- Advanced Research Institute of Multidisciplinary Science Beijing Institute of Technology Beijing 100081 China
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6
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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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7
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Park C, Lee K, Koo M, Park C. Soft Ferroelectrics Enabling High-Performance Intelligent Photo Electronics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2004999. [PMID: 33338279 DOI: 10.1002/adma.202004999] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/27/2020] [Indexed: 06/12/2023]
Abstract
Soft ferroelectrics based on organic and organic-inorganic hybrid materials have gained much interest among researchers owing to their electrically programmable and remnant polarization. This allows for the development of numerous flexible, foldable, and stretchable nonvolatile memories, when combined with various crystal engineering approaches to optimize their performance. Soft ferroelectrics have been recently considered to have an important role in the emerging human-connected electronics that involve diverse photoelectronic elements, particularly those requiring precise programmable electric fields, such as tactile sensors, synaptic devices, displays, photodetectors, and solar cells for facile human-machine interaction, human safety, and sustainability. This paper provides a comprehensive review of the recent developments in soft ferroelectric materials with an emphasis on their ferroelectric switching principles and their potential application in human-connected intelligent electronics. Based on the origins of ferroelectric atomic and/or molecular switching, the soft ferroelectrics are categorized into seven subgroups. In this review, the efficiency of soft ferroelectrics with their distinct ferroelectric characteristics utilized in various human-connected electronic devices with programmable electric field is demonstrated. This review inspires further research to utilize the remarkable functionality of soft electronics.
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Affiliation(s)
- Chanho Park
- Department of Materials Science and Engineering, Yonsei University, Yonsei-ro 50, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Kyuho Lee
- Department of Materials Science and Engineering, Yonsei University, Yonsei-ro 50, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Min Koo
- Department of Materials Science and Engineering, Yonsei University, Yonsei-ro 50, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Cheolmin Park
- Department of Materials Science and Engineering, Yonsei University, Yonsei-ro 50, Seodaemun-gu, Seoul, 03722, Republic of Korea
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8
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Zhang Y, Dai J, Zhong X, Zhang D, Zhong G, Li J. Probing Ultrafast Dynamics of Ferroelectrics by Time-Resolved Pump-Probe Spectroscopy. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2102488. [PMID: 34632722 PMCID: PMC8596111 DOI: 10.1002/advs.202102488] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 07/29/2021] [Indexed: 05/26/2023]
Abstract
Ferroelectric materials have been a key research topic owing to their wide variety of modern electronic and photonic applications. For the quick exploration of higher operating speed, smaller size, and superior efficiencies of novel ferroelectric devices, the ultrafast dynamics of ferroelectrics that directly reflect their respond time and lifetimes have drawn considerable attention. Driven by time-resolved pump-probe spectroscopy that allows for probing, controlling, and modulating dynamic processes of ferroelectrics in real-time, much research efforts have been made to understand and exploit the ultrafast dynamics of ferroelectric. Herein, the current state of ultrafast dynamic features of ferroelectrics tracked by time-resolved pump-probe spectroscopy is reviewed, which includes ferroelectrics order parameters of polarization, lattice, spin, electronic excitation, and their coupling. Several potential perspectives and possible further applications combining ultrafast pump-probe spectroscopy and ferroelectrics are also presented. This review offers a clear guidance of ultrafast dynamics of ferroelectric orders, which may promote the rapid development of next-generation devices.
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Affiliation(s)
- Yuan Zhang
- Shenzhen Key Laboratory of Nanobiomechanics, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, 518055, China
| | - Junfeng Dai
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Xiangli Zhong
- School of Materials Science and Engineering, Xiangtan University, Xiangtan, Hunan, 411105, China
| | - Dongwen Zhang
- Department of Physics, College of Liberal Arts and Sciences, National University of Defense Technology, Changsha, Hunan, 410073, China
| | - Gaokuo Zhong
- Shenzhen Key Laboratory of Nanobiomechanics, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, 518055, China
| | - Jiangyu Li
- Shenzhen Key Laboratory of Nanobiomechanics, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, 518055, China
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Guangdong Provincial Key Laboratory of Functional Oxide Materials and Devices, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
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9
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Yamakawa H, Miyamoto T, Morimoto T, Takamura N, Liang S, Yoshimochi H, Terashige T, Kida N, Suda M, Yamamoto HM, Mori H, Miyagawa K, Kanoda K, Okamoto H. Terahertz-field-induced polar charge order in electronic-type dielectrics. Nat Commun 2021; 12:953. [PMID: 33574221 PMCID: PMC7878852 DOI: 10.1038/s41467-021-20925-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 12/29/2020] [Indexed: 11/09/2022] Open
Abstract
Ultrafast electronic-phase change in solids by light, called photoinduced phase transition, is a central issue in the field of non-equilibrium quantum physics, which has been developed very recently. In most of those phenomena, charge or spin orders in an original phase are melted by photocarrier generations, while an ordered state is usually difficult to be created from a non-ordered state by a photoexcitation. Here, we demonstrate that a strong terahertz electric-field pulse changes a Mott insulator of an organic molecular compound in κ-(ET)2Cu[N(CN)2]Cl (ET = bis(ethylenedithio)tetrathiafulvalene), to a macroscopically polarized charge-order state; herein, electronic ferroelectricity is induced by the collective intermolecular charge transfers in each dimer. In contrast, in an isostructural compound, κ-(ET)2Cu2(CN)3, which shows the spin-liquid state at low temperatures, a similar polar charge order is not stabilized by the same terahertz pulse. From the comparative studies of terahertz-field-induced second-harmonic-generation and reflectivity changes in the two compounds, we suggest the possibility that a coupling of charge and spin degrees of freedom would play important roles in the stabilization of polar charge order.
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Affiliation(s)
- H Yamakawa
- Department of Advanced Materials Science, University of Tokyo, Chiba, 277-8561, Japan
| | - T Miyamoto
- Department of Advanced Materials Science, University of Tokyo, Chiba, 277-8561, Japan.
| | - T Morimoto
- Department of Advanced Materials Science, University of Tokyo, Chiba, 277-8561, Japan
| | - N Takamura
- Department of Advanced Materials Science, University of Tokyo, Chiba, 277-8561, Japan
| | - S Liang
- Department of Advanced Materials Science, University of Tokyo, Chiba, 277-8561, Japan
| | - H Yoshimochi
- Department of Applied Physics, University of Tokyo, Bunkyo-Ku, 113-8656, Japan
| | - T Terashige
- AIST-UTokyo Advanced Operand-Measurement Technology Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology, Chiba, 277-8589, Japan
| | - N Kida
- Department of Advanced Materials Science, University of Tokyo, Chiba, 277-8561, Japan
| | - M Suda
- Division of Functional Molecular Systems, Research Center of Integrative Molecular Systems (CIMoS), Institute for Molecular Science, Okazaki, 444-8585, Japan.,Department of Molecular Engineering, Kyoto University, Kyoto, 615-8510, Japan
| | - H M Yamamoto
- Division of Functional Molecular Systems, Research Center of Integrative Molecular Systems (CIMoS), Institute for Molecular Science, Okazaki, 444-8585, Japan
| | - H Mori
- Institute for Solid State Physics, University of Tokyo, Chiba, 277-8581, Japan
| | - K Miyagawa
- Department of Applied Physics, University of Tokyo, Bunkyo-Ku, 113-8656, Japan
| | - K Kanoda
- Department of Applied Physics, University of Tokyo, Bunkyo-Ku, 113-8656, Japan
| | - H Okamoto
- Department of Advanced Materials Science, University of Tokyo, Chiba, 277-8561, Japan. .,AIST-UTokyo Advanced Operand-Measurement Technology Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology, Chiba, 277-8589, Japan.
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10
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Cassabaum AA, Bera K, Rich CC, Nebgen BR, Kwang SY, Clapham ML, Frontiera RR. Femtosecond stimulated Raman spectro-microscopy for probing chemical reaction dynamics in solid-state materials. J Chem Phys 2020; 153:030901. [DOI: 10.1063/5.0009976] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Affiliation(s)
- Alyssa A. Cassabaum
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Kajari Bera
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Christopher C. Rich
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Bailey R. Nebgen
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Siu Yi Kwang
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Margaret L. Clapham
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Renee R. Frontiera
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA
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11
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Reconfiguration of magnetic domain structures of ErFeO 3 by intense terahertz free electron laser pulses. Sci Rep 2020; 10:7321. [PMID: 32355246 PMCID: PMC7193561 DOI: 10.1038/s41598-020-64147-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Accepted: 04/13/2020] [Indexed: 11/14/2022] Open
Abstract
Understanding the interaction between intense terahertz (THz) electromagnetic fields and spin systems has been gaining importance in modern spintronics research as a unique pathway to realize ultrafast macroscopic magnetization control. In this work, we used intense THz pulses with pulse energies in the order of 10 mJ/pulse generated from the terahertz free electron laser (THz-FEL) to irradiate the ferromagnetic domains of ErFeO3 single crystal. It was found that the domain shape can be locally reconfigured by irradiating the THz − FEL pulses near the domain boundary. Observed domain reconfiguration mechanism can be phenomenologically understood by the combination of depinning effect and the entropic force due to local thermal gradient exerted by terahertz irradiation. Our finding opens up a new possibility of realizing thermal-spin effects at THz frequency ranges by using THz-FEL pulses.
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12
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Kinoshita Y, Kida N, Magasaki Y, Morimoto T, Terashige T, Miyamoto T, Okamoto H. Strong Terahertz Radiation via Rapid Polarization Reduction in Photoinduced Ionic-To-Neutral Transition in Tetrathiafulvalene-p-Chloranil. PHYSICAL REVIEW LETTERS 2020; 124:057402. [PMID: 32083935 DOI: 10.1103/physrevlett.124.057402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Revised: 05/06/2019] [Accepted: 01/08/2020] [Indexed: 06/10/2023]
Abstract
Terahertz lights are usually generated through the optical rectification process within a femtosecond laser pulse in noncentrosymmetric materials. Here, we report a new generation mechanism of terahertz lights based upon a photoinduced phase transition, in which an electronic structure is rapidly changed by a photoirradiation. When a ferroelectric organic molecular compound, tetrathiafulvalene-p-chloranil, is excited by a femtosecond laser pulse, the ionic-to-neutral transition is driven and simultaneously a strong terahertz radiation is produced. By analyzing the terahertz electric-field waveforms and their dependence on the polarization direction of the incident laser pulse, we demonstrate that the terahertz radiation originates from the ultrafast decrease of the spontaneous polarization in the photoinduced ionic-to-neutral transition. The efficiency of the observed terahertz radiation via the photoinduced phase transition mechanism is found to be much higher than that via the optical rectification in the same material and in a typical terahertz emitter, ZnTe.
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Affiliation(s)
- Yuto Kinoshita
- Department of Advanced Materials Science, The University of Tokyo, 5-1-5 Kashiwa-no-ha, Chiba 277-8561, Japan
| | - Noriaki Kida
- Department of Advanced Materials Science, The University of Tokyo, 5-1-5 Kashiwa-no-ha, Chiba 277-8561, Japan
| | - Yusuke Magasaki
- Department of Advanced Materials Science, The University of Tokyo, 5-1-5 Kashiwa-no-ha, Chiba 277-8561, Japan
| | - Takeshi Morimoto
- Department of Advanced Materials Science, The University of Tokyo, 5-1-5 Kashiwa-no-ha, Chiba 277-8561, Japan
| | - Tsubasa Terashige
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology, Chiba 277-8568, Japan
| | - Tatsuya Miyamoto
- Department of Advanced Materials Science, The University of Tokyo, 5-1-5 Kashiwa-no-ha, Chiba 277-8561, Japan
| | - Hiroshi Okamoto
- Department of Advanced Materials Science, The University of Tokyo, 5-1-5 Kashiwa-no-ha, Chiba 277-8561, Japan
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology, Chiba 277-8568, Japan
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13
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Jiang H, Hu W. The Emergence of Organic Single-Crystal Electronics. Angew Chem Int Ed Engl 2019; 59:1408-1428. [PMID: 30927312 DOI: 10.1002/anie.201814439] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 03/25/2019] [Indexed: 12/14/2022]
Abstract
Organic semiconducting single crystals are perfect for both fundamental and application-oriented research due to the advantages of free grain boundaries, few defects, and minimal traps and impurities, as well as their low-temperature processability, high flexibility, and low cost. Carrier mobilities of greater than 10 cm2 V-1 s-1 in some organic single crystals indicate a promising application in electronic devices. The progress made, including the molecular structures and fabrication technologies of organic single crystals, is introduced and organic single-crystal electronic devices, including field-effect transistors, phototransistors, p-n heterojunctions, and circuits, are summarized. Organic two-dimensional single crystals, cocrystals, and large single crystals, together with some potential applications, are introduced. A state-of-the-art overview of organic single-crystal electronics, with their challenges and prospects, is also provided.
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Affiliation(s)
- Hui Jiang
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Sciences, Tianjin University, No. 92#, Weijin Road, Tianjin, 300072, China.,School of Materials Science and Engineering, Nanyang Technological University, 639798, Singapore, Singapore
| | - Wenping Hu
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Sciences, Tianjin University, No. 92#, Weijin Road, Tianjin, 300072, China.,Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
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14
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Affiliation(s)
- Hui Jiang
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences Department of Chemistry School of Sciences Tianjin University No. 92#, Weijin Road Tianjin 300072 China
- School of Materials Science and Engineering Nanyang Technological University 639798 Singapore Singapur
| | - Wenping Hu
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences Department of Chemistry School of Sciences Tianjin University No. 92#, Weijin Road Tianjin 300072 China
- Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 China
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15
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Wang J, Li A, Xu S, Song C, Geng Y, Ye L, Zhang H, Xu W. Solvation-Enhanced Intermolecular Charge Transfer Interaction in Organic Cocrystals: Enlarged C-C Surface Close Contact in Mixed Packing between PTZ and TCNB. ACS OMEGA 2019; 4:10424-10430. [PMID: 31460137 PMCID: PMC6648522 DOI: 10.1021/acsomega.9b01083] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 06/05/2019] [Indexed: 05/09/2023]
Abstract
The mixed π-π packing of the donor (D) and acceptor (A) molecules is the highlighting feature of the intermolecular interactions following charge transfer (CT) issues in organic cocrystal systems. There is an inverse relationship between the D-A interplanar distance and the intermolecular CT interaction. However, the D-A C-C surface close contact (relative areas) on the intermolecular CT interactions in organic cocrystal systems is rarely investigated. Herein, we designed and constructed a novel cocrystal and its solvate cocrystal. The structural and electrostatic potential analyses suggest that the solvation destroys the N-H···N hydrogen bond interaction between phenothiazine (PTZ) and 1,2,4,5-tetracyanobenzene (TCNB), which causes the TCNB molecules to have a 90° rotation along the normal axis of the PTZ plane. Thus, the D-A C-C surface close contact is enlarged, strengthening the intermolecular π-π stacking interactions and intermolecular CT interaction between PTZ and TCNB, which are further evidenced by the absorption and Raman spectroscopic analyses. This study provides rare evidence of the enlarged C-C surface close contact in the mixed packing between D and A that greatly contributes to the intermolecular CT interaction in a D-A cocrystal system. It also provides a deeper understanding of the role of solvation in the structure-property relationship of organic cocrystal materials.
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Affiliation(s)
- Jing Wang
- State
Key Laboratory of Supramolecular Structure and Materials, College
of Chemistry and College of Physics, Jilin University, Changchun 130012, P. R. China
| | - Aisen Li
- State
Key Laboratory of Supramolecular Structure and Materials, College
of Chemistry and College of Physics, Jilin University, Changchun 130012, P. R. China
| | - Shuping Xu
- State
Key Laboratory of Supramolecular Structure and Materials, College
of Chemistry and College of Physics, Jilin University, Changchun 130012, P. R. China
| | - Chongping Song
- State
Key Laboratory of Supramolecular Structure and Materials, College
of Chemistry and College of Physics, Jilin University, Changchun 130012, P. R. China
| | - Yijia Geng
- State
Key Laboratory of Supramolecular Structure and Materials, College
of Chemistry and College of Physics, Jilin University, Changchun 130012, P. R. China
| | - Ling Ye
- State
Key Laboratory of Supramolecular Structure and Materials, College
of Chemistry and College of Physics, Jilin University, Changchun 130012, P. R. China
| | - Houyu Zhang
- State
Key Laboratory of Supramolecular Structure and Materials, College
of Chemistry and College of Physics, Jilin University, Changchun 130012, P. R. China
| | - Weiqing Xu
- State
Key Laboratory of Supramolecular Structure and Materials, College
of Chemistry and College of Physics, Jilin University, Changchun 130012, P. R. China
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16
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Yang Y, Liu G, Liu J, Wei M, Wang Z, Hao X, Maheswar Repaka DV, Ramanujan RV, Tao X, Qin W, Zhang Q. Anisotropic Magnetoelectric Coupling and Cotton-Mouton Effects in the Organic Magnetic Charge-Transfer Complex Pyrene-F 4TCNQ. ACS APPLIED MATERIALS & INTERFACES 2018; 10:44654-44659. [PMID: 30507119 DOI: 10.1021/acsami.8b16848] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Magnetoelectric coupling is of high current interest because of its potential applications in multiferroic memory devices. Although magnetoelectric coupling has been widely investigated in inorganic materials, such observations in organic materials are extremely rare. Here, we report our discovery that organic charge-transfer (CT) complex pyrene-2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (pyrene-F4TCNQ) can display anisotropic magnetoelectric coupling. Investigation of the crystal structure of pyrene-F4TCNQ complex demonstrates that the magnetoelectric coupling coefficient along the π-π interaction direction is much larger than the value along other directions. Furthermore, magnetoelectric coupling and magnetization can be tuned by changing the fluorine content in complexes. Besides, the Cotton-Mouton effect in pyrene-F4TCNQ is observed, enabling the control of optomagnetic devices. These results can pave the way for a new method for the future development of organic CT complexes and their applications in perpendicular memory devices and energy-transfer-related multiferroics.
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Affiliation(s)
- Yuying Yang
- School of Physics, State Key Laboratory of Crystal Materials , Shandong University , Jinan 250100 , China
| | - Guangfeng Liu
- School of Materials Science and Engineering , Nanyang Technological University , 50 Nanyang Avenue , 639798 , Singapore
| | - Jie Liu
- School of Physics, State Key Laboratory of Crystal Materials , Shandong University , Jinan 250100 , China
| | - Mengmeng Wei
- School of Physics, State Key Laboratory of Crystal Materials , Shandong University , Jinan 250100 , China
| | - Zhongxuan Wang
- School of Physics, State Key Laboratory of Crystal Materials , Shandong University , Jinan 250100 , China
| | - Xiaotao Hao
- School of Physics, State Key Laboratory of Crystal Materials , Shandong University , Jinan 250100 , China
- ARC Centre of Excellence in Exciton Science, School of Chemistry , The University of Melbourne , Parkville , Victoria 3010 , Australia
| | - D V Maheswar Repaka
- School of Materials Science and Engineering , Nanyang Technological University , 50 Nanyang Avenue , 639798 , Singapore
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences , Nanyang Technological University , 21 Nanyang Link , 637371 , Singapore
| | - Raju V Ramanujan
- School of Materials Science and Engineering , Nanyang Technological University , 50 Nanyang Avenue , 639798 , Singapore
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences , Nanyang Technological University , 21 Nanyang Link , 637371 , Singapore
| | - Xutang Tao
- School of Physics, State Key Laboratory of Crystal Materials , Shandong University , Jinan 250100 , China
| | - Wei Qin
- School of Physics, State Key Laboratory of Crystal Materials , Shandong University , Jinan 250100 , China
| | - Qichun Zhang
- School of Materials Science and Engineering , Nanyang Technological University , 50 Nanyang Avenue , 639798 , Singapore
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17
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Ultrafast polarization control by terahertz fields via π-electron wavefunction changes in hydrogen-bonded molecular ferroelectrics. Sci Rep 2018; 8:15014. [PMID: 30301914 PMCID: PMC6177455 DOI: 10.1038/s41598-018-33076-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 09/21/2018] [Indexed: 12/03/2022] Open
Abstract
Rapid polarization control by an electric field in ferroelectrics is important to realize high-frequency modulation of light, which has potential applications in optical communications. To achieve this, a key strategy is to use an electronic part of ferroelectric polarization. A hydrogen-bonded molecular ferroelectric, croconic acid, is a good candidate, since π-electron polarization within each molecule is theoretically predicted to play a significant role in the ferroelectric-state formation, as well as the proton displacements. Here, we show that a sub-picosecond polarization modulation is possible in croconic acid using a terahertz pulse. The terahertz-pulse-pump second-harmonic-generation-probe and optical-reflectivity-probe spectroscopy reveal that the amplitude of polarization modulation reaches 10% via the electric-field-induced modifications of π-electron wavefunctions. Moreover, the measurement of electric-field-induced changes in the infrared molecular vibrational spectrum elucidates that the contribution of proton displacements to the polarization modulation is negligibly small. These results demonstrate the electronic nature of polarization in hydrogen-bonded molecular ferroelectrics. The ultrafast polarization control via π-electron systems observed in croconic acid is expected to be possible in many other hydrogen-bonded molecular ferroelectrics and utilized for future high-speed optical-modulation devices.
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18
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Dynamic molecular crystals with switchable physical properties. Nat Chem 2018; 8:644-56. [PMID: 27325090 DOI: 10.1038/nchem.2547] [Citation(s) in RCA: 513] [Impact Index Per Article: 85.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 05/09/2016] [Indexed: 02/07/2023]
Abstract
The development of molecular materials whose physical properties can be controlled by external stimuli - such as light, electric field, temperature, and pressure - has recently attracted much attention owing to their potential applications in molecular devices. There are a number of ways to alter the physical properties of crystalline materials. These include the modulation of the spin and redox states of the crystal's components, or the incorporation within the crystalline lattice of tunable molecules that exhibit stimuli-induced changes in their molecular structure. A switching behaviour can also be induced by changing the molecular orientation of the crystal's components, even in cases where the overall molecular structure is not affected. Controlling intermolecular interactions within a molecular material is also an effective tool to modulate its physical properties. This Review discusses recent advances in the development of such stimuli-responsive, switchable crystalline compounds - referred to here as dynamic molecular crystals - and suggests how different approaches can serve to prepare functional materials.
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19
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Ultrafast magnetization modulation induced by the electric field component of a terahertz pulse in a ferromagnetic-semiconductor thin film. Sci Rep 2018; 8:6901. [PMID: 29720716 PMCID: PMC5931997 DOI: 10.1038/s41598-018-25266-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 04/13/2018] [Indexed: 11/18/2022] Open
Abstract
High-speed magnetization control of ferromagnetic films using light pulses is attracting considerable attention and is increasingly important for the development of spintronic devices. Irradiation with a nearly monocyclic terahertz pulse, which can induce strong electromagnetic fields in ferromagnetic films within an extremely short time of less than ~1 ps, is promising for damping-free high-speed coherent control of the magnetization. Here, we successfully observe a terahertz response in a ferromagnetic-semiconductor thin film. In addition, we find that a similar terahertz response is observed even in a non-magnetic semiconductor and reveal that the electric-field component of the terahertz pulse plays a crucial role in the magnetization response through the spin-carrier interactions in a ferromagnetic-semiconductor thin film. Our findings will provide new guidelines for designing materials suitable for ultrafast magnetization reversal.
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20
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Yamakawa H, Miyamoto T, Morimoto T, Terashige T, Yada H, Kida N, Suda M, Yamamoto HM, Kato R, Miyagawa K, Kanoda K, Okamoto H. Mott transition by an impulsive dielectric breakdown. NATURE MATERIALS 2017; 16:1100-1105. [PMID: 28825731 DOI: 10.1038/nmat4967] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Accepted: 07/11/2017] [Indexed: 06/07/2023]
Abstract
The transition of a Mott insulator to metal, the Mott transition, can occur via carrier doping by elemental substitution, and by photoirradiation, as observed in transition-metal compounds and in organic materials. Here, we show that the application of a strong electric field can induce a Mott transition by a new pathway, namely through impulsive dielectric breakdown. Irradiation of a terahertz electric-field pulse on an ET-based compound, κ-(ET) 2Cu[N(CN) 2]Br (ET:bis(ethylenedithio)tetrathiafulvalene), collapses the original Mott gap of ∼30 meV with a ∼0.1 ps time constant after doublon-holon pair productions by quantum tunnelling processes, as indicated by the nonlinear increase of Drude-like low-energy spectral weights. Additionally, we demonstrate metallization using this method is faster than that by a femtosecond laser-pulse irradiation and that the transition dynamics are more electronic and coherent. Thus, strong terahertz-pulse irradiation is an effective approach to achieve a purely electronic Mott transition, enhancing the understanding of its quantum nature.
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Affiliation(s)
- H Yamakawa
- Department of Advanced Materials Science, University of Tokyo, Chiba 277-8561, Japan
| | - T Miyamoto
- Department of Advanced Materials Science, University of Tokyo, Chiba 277-8561, Japan
| | - T Morimoto
- Department of Advanced Materials Science, University of Tokyo, Chiba 277-8561, Japan
| | - T Terashige
- Department of Advanced Materials Science, University of Tokyo, Chiba 277-8561, Japan
| | - H Yada
- Department of Advanced Materials Science, University of Tokyo, Chiba 277-8561, Japan
| | - N Kida
- Department of Advanced Materials Science, University of Tokyo, Chiba 277-8561, Japan
| | - M Suda
- Division of Functional Molecular Systems, Research Center of Integrative Molecular Systems (CIMoS), Institute for Molecular Science, Okazaki 444-8585, Japan
| | - H M Yamamoto
- Division of Functional Molecular Systems, Research Center of Integrative Molecular Systems (CIMoS), Institute for Molecular Science, Okazaki 444-8585, Japan
- RIKEN, Wako 351-0198, Japan
| | - R Kato
- RIKEN, Wako 351-0198, Japan
| | - K Miyagawa
- Department of Applied Physics, University of Tokyo, Bunkyo-ku 113-8656, Japan
| | - K Kanoda
- Department of Applied Physics, University of Tokyo, Bunkyo-ku 113-8656, Japan
| | - H Okamoto
- Department of Advanced Materials Science, University of Tokyo, Chiba 277-8561, Japan
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21
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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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22
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Ultrafast Electron and Molecular Dynamics in Photoinduced and Electric-Field-Induced Neutral–Ionic Transitions. CRYSTALS 2017. [DOI: 10.3390/cryst7050132] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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23
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THz Electric Field-Induced Second Harmonic Generation in Inorganic Ferroelectric. Sci Rep 2017; 7:687. [PMID: 28386081 PMCID: PMC5429639 DOI: 10.1038/s41598-017-00704-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 03/08/2017] [Indexed: 11/16/2022] Open
Abstract
Second Harmonic Generation induced by the electric field of a strong nearly single-cycle terahertz pulse with the peak amplitude of 300 kV/cm is studied in a classical inorganic ferroelectric thin film of (Ba0.8Sr0.2)TiO3. The dependences of the SHG intensity on the polarization of the incoming light is revealed and interpreted in terms of electric polarization induced in the plane of the film. As the THz pulse pumps the medium in the range of phononic excitations, the induced polarization is explained as a dynamical change of the ferrolectric order parameter. It is estimated that under action of the THz pulse the ferroelectric order parameter acquires an in-plane component up to 6% of the net polarization.
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24
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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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25
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Bancelin S, Vigne S, Hossain N, Chaker M, Légaré F. Nonlinear optical properties of calcium barium niobate epitaxial thin films. OPTICS EXPRESS 2016; 24:17497-17504. [PMID: 27464195 DOI: 10.1364/oe.24.017497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We investigate the potential of epitaxial calcium barium niobate (CBN) thin film grown by pulsed laser deposition for optical frequency conversion. Using second harmonic generation (SHG), we analyze the polarization response of the generated signal to determine the ratios d15 / d32 and d33 / d32 of the three independent components of the second-order nonlinear susceptibility tensor in CBN thin film. In addition, a detailed comparison to the signal intensity obtained in a y-cut quartz allows us to measure the absolute value of these components in CBN thin film: d15 = 5 ± 2 pm / V, d32 = 3.1 ± 0.6 pm / V and d33 = 9 ± 2 pm / V.
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26
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Yamakawa H, Miyamoto T, Morimoto T, Yada H, Kinoshita Y, Sotome M, Kida N, Yamamoto K, Iwano K, Matsumoto Y, Watanabe S, Shimoi Y, Suda M, Yamamoto HM, Mori H, Okamoto H. Novel electronic ferroelectricity in an organic charge-order insulator investigated with terahertz-pump optical-probe spectroscopy. Sci Rep 2016; 6:20571. [PMID: 26864779 PMCID: PMC4750076 DOI: 10.1038/srep20571] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 01/06/2016] [Indexed: 11/18/2022] Open
Abstract
In electronic-type ferroelectrics, where dipole moments produced by the variations of electron configurations are aligned, the polarization is expected to be rapidly controlled by electric fields. Such a feature can be used for high-speed electric-switching and memory devices. Electronic-type ferroelectrics include charge degrees of freedom, so that they are sometimes conductive, complicating dielectric measurements. This makes difficult the exploration of electronic-type ferroelectrics and the understanding of their ferroelectric nature. Here, we show unambiguous evidence for electronic ferroelectricity in the charge-order (CO) phase of a prototypical ET-based molecular compound, α-(ET)2I3 (ET:bis(ethylenedithio)tetrathiafulvalene), using a terahertz pulse as an external electric field. Terahertz-pump second-harmonic-generation(SHG)-probe and optical-reflectivity-probe spectroscopy reveal that the ferroelectric polarization originates from intermolecular charge transfers and is inclined 27° from the horizontal CO stripe. These features are qualitatively reproduced by the density-functional-theory calculation. After sub-picosecond polarization modulation by terahertz fields, prominent oscillations appear in the reflectivity but not in the SHG-probe results, suggesting that the CO is coupled with molecular displacements, while the ferroelectricity is electronic in nature. The results presented here demonstrate that terahertz-pump optical-probe spectroscopy is a powerful tool not only for rapidly controlling polarizations, but also for clarifying the mechanisms of ferroelectricity.
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Affiliation(s)
- H Yamakawa
- Department of Advanced Materials Science, The University of Tokyo, Chiba 277-8561, Japan
| | - T Miyamoto
- Department of Advanced Materials Science, The University of Tokyo, Chiba 277-8561, Japan
| | - T Morimoto
- Department of Advanced Materials Science, The University of Tokyo, Chiba 277-8561, Japan
| | - H Yada
- Department of Advanced Materials Science, The University of Tokyo, Chiba 277-8561, Japan
| | - Y Kinoshita
- Department of Advanced Materials Science, The University of Tokyo, Chiba 277-8561, Japan
| | - M Sotome
- Department of Advanced Materials Science, The University of Tokyo, Chiba 277-8561, Japan
| | - N Kida
- Department of Advanced Materials Science, The University of Tokyo, Chiba 277-8561, Japan
| | - K Yamamoto
- Department of Applied Physics, Okayama University of Science, Okayama 700-0005, Japan
| | - K Iwano
- Institute of Materials Structure Science, Graduate University for Advanced Studies, High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801, Japan
| | - Y Matsumoto
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8568, Japan
| | - S Watanabe
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8568, Japan
| | - Y Shimoi
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8568, Japan
| | - M Suda
- Division of Functional Molecular Systems, Research Centre of Integrative Molecular Systems (CIMoS), Institute for Molecular Science, Okazaki 444-8585, Japan
| | - H M Yamamoto
- Division of Functional Molecular Systems, Research Centre of Integrative Molecular Systems (CIMoS), Institute for Molecular Science, Okazaki 444-8585, Japan.,RIKEN, Wako 351-0198, Japan
| | - H Mori
- The Institute for Solid State Physics, The University of Tokyo, Chiba 277-8581, Japan
| | - H Okamoto
- Department of Advanced Materials Science, The University of Tokyo, Chiba 277-8561, Japan
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27
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Di Maiolo F, Sissa C, Painelli A. Combining intra- and intermolecular charge-transfer: a new strategy towards molecular ferromagnets and multiferroics. Sci Rep 2016; 6:19682. [PMID: 26790963 PMCID: PMC4726343 DOI: 10.1038/srep19682] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 12/14/2015] [Indexed: 11/09/2022] Open
Abstract
Organic ferroelectric materials are currently a hot research topic, with mixed stack charge transfer crystals playing a prominent role with their large, electronic-in-origin polarization and the possibility to tune the transition temperature down to the quantum limit and/or to drive the ferroelectric transition via an optical stimulus. By contrast, and in spite of an impressive research effort, organic ferromagnets are rare and characterized by very low transition temperatures. Coexisting magnetic and electric orders in multiferroics offer the possibility to control magnetic (electric) properties by an applied electric (magnetic) field with impressive technological potential. Only few examples of multiferroics are known today, based on inorganics materials. Here we demonstrate that, by decorating mixed stack charge transfer crystals with organic radicals, a new family of robust molecular ferromagnets can be designed, stable up to ambient temperature, and with a clear tendency towards multiferroic behaviour.
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Affiliation(s)
- Francesco Di Maiolo
- Dipartimento di Chimica, Università di Parma, Parco Area delle Scienze 17/A, 43124, Parma, Italy
| | - Cristina Sissa
- Dipartimento di Chimica, Università di Parma, Parco Area delle Scienze 17/A, 43124, Parma, Italy
| | - Anna Painelli
- Dipartimento di Chimica, Università di Parma, Parco Area delle Scienze 17/A, 43124, Parma, Italy
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28
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Chen L, Yang Y, Gui Z, Sando D, Bibes M, Meng XK, Bellaiche L. Large Elasto-Optic Effect in Epitaxial PbTiO(3) Films. PHYSICAL REVIEW LETTERS 2015; 115:267602. [PMID: 26765030 DOI: 10.1103/physrevlett.115.267602] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Indexed: 06/05/2023]
Abstract
First-principles calculations are performed to investigate the elasto-optic properties of four different structural phases in (001) epitaxial PbTiO(3) films under tensile strain: a tetragonal (T) phase and an orthorhombic (O) phase, which are the ground states for small and large strain, respectively, and two low-symmetry, monoclinic phases of Cm and Pm symmetries that have low total energy in the intermediate strain range. It is found that the refractive indices of the T and O phases respond differently to epitaxial strain, evidenced by a change of sign of their effective elasto-optic coefficients, and as a result of presently discovered correlations between refractive index, axial ratio, and magnitude of the ferroelectric polarization. The difference in refractive indices between T and O and the existence of such correlations naturally lead to large elasto-optic coefficients in the Cm and Pm states in the intermediate strain range, because Cm structurally bridges the T and O phases (via polarization rotation and a rapid change of its axial ratio) and Pm adopts a similar axial ratio and polarization magnitude to Cm. The present results therefore broaden the palette of functionalities of ferroelectric materials, and suggest new routes to generate systems with unprecedentedly large elasto-optic conversion.
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Affiliation(s)
- Lan Chen
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China
| | - Yurong Yang
- Department of Physics and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Zhigang Gui
- Department of Physics and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - D Sando
- School of Materials Science and Engineering, University of New South Wales, Kensington, New South Wales 2052, Australia
| | - M Bibes
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France
| | - X K Meng
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China
| | - L Bellaiche
- Department of Physics and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
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29
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Chen F, Goodfellow J, Liu S, Grinberg I, Hoffmann MC, Damodaran AR, Zhu Y, Zalden P, Zhang X, Takeuchi I, Rappe AM, Martin LW, Wen H, Lindenberg AM. Ultrafast Terahertz Gating of the Polarization and Giant Nonlinear Optical Response in BiFeO3 Thin Films. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:6371-5. [PMID: 26389651 DOI: 10.1002/adma.201502975] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 07/26/2015] [Indexed: 05/24/2023]
Abstract
Terahertz pulses are applied as an all-optical bias to ferroelectric thin-film BiFeO3 while monitoring the time-dependent ferroelectric polarization through its nonlinear optical response. Modulations in the intensity of the second harmonic light generated by the film correspond to on-off ratios of 220× gateable on femtosecond timescales. Polarization modulations comparable to the built-in static polarization are observed.
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Affiliation(s)
- Frank Chen
- SIMES Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
- Department of Electrical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - John Goodfellow
- SIMES Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Shi Liu
- The Makineni Theoretical Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Ilya Grinberg
- The Makineni Theoretical Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | | | - Anoop R Damodaran
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Yi Zhu
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Peter Zalden
- SIMES Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - Xiaohang Zhang
- Department of Materials Science and Engineering, University of Maryland, College Park, MD, 20742, USA
| | - Ichiro Takeuchi
- Department of Materials Science and Engineering, University of Maryland, College Park, MD, 20742, USA
| | - Andrew M Rappe
- The Makineni Theoretical Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Lane W Martin
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Haidan Wen
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Aaron M Lindenberg
- SIMES Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305, USA
- PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
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30
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Feng HJ, Yang K, Deng W, Li M, Wang M, Duan B, Liu F, Tian J, Guo X. The origin of enhanced optical absorption of the BiFeO3/ZnO heterojunction in the visible and terahertz regions. Phys Chem Chem Phys 2015; 17:26930-6. [PMID: 26403497 DOI: 10.1039/c5cp04389a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Optical absorption is improved for the BiFeO3/ZnO heterostructure prepared by a sol-gel process, especially, in the terahertz energy region. A dipole-corrected slab model is used to describe the bilayer film, and first-principles calculations agree with the experiments which present unambiguous explanation for the enhancement of the optical properties. Two-dimensional electrons in the ZnO side of the heterostructure are found to play an essential role in forming the photoinduced carriers and the enhancement of the absorption. The conducting layers tend to penetrate into the interface and decrease the band gap, leading to the transport of carriers through the interface to the BiFeO3 side. The photoinduced carriers can be separated by the ferroelectric domains in BiFeO3, and this mechanism makes the heterostructure an ideal candidate for BiFeO3-based ferroelectric photovoltaic cells.
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Affiliation(s)
- Hong-Jian Feng
- School of Physics, State Key Lab Incubation Base of Photoelectric Technology and Functional Materials, and International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Northwest University, Xi'an 710069, People's Republic of China.
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31
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Qin W, Chen X, Li H, Gong M, Yuan G, Grossman JC, Wuttig M, Ren S. Room Temperature Multiferroicity of Charge Transfer Crystals. ACS NANO 2015; 9:9373-9379. [PMID: 26257033 DOI: 10.1021/acsnano.5b03558] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Room temperature multiferroics has been a frontier research field by manipulating spin-driven ferroelectricity or charge-order-driven magnetism. Charge-transfer crystals based on electron donor and acceptor assembly, exhibiting simultaneous spin ordering, are drawing significant interests for the development of all-organic magnetoelectric multiferroics. Here, we report that a remarkable anisotropic magnetization and room temperature multiferroicity can be achieved through assembly of thiophene donor and fullerene acceptor. The crystal motif directs the dimensional and compositional control of charge-transfer networks that could switch magnetization under external stimuli, thereby opening up an attractive class of all-organic nanoferronics.
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Affiliation(s)
- Wei Qin
- Department of Mechanical Engineering, Temple University , Philadelphia, Pennsylvania 19122, United States
| | - Xiaomin Chen
- Department of Materials Science and Engineering, University of Maryland , College Park, Maryland 20742, United States
- School of Materials Science and Engineering, Nanjing University of Science and Technology , Nanjing, China
| | - Huashan Li
- Department of Materials Science and Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Maogang Gong
- Department of Mechanical Engineering, Temple University , Philadelphia, Pennsylvania 19122, United States
| | - Guoliang Yuan
- School of Materials Science and Engineering, Nanjing University of Science and Technology , Nanjing, China
| | - Jeffrey C Grossman
- Department of Materials Science and Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Manfred Wuttig
- Department of Materials Science and Engineering, University of Maryland , College Park, Maryland 20742, United States
| | - Shenqiang Ren
- Department of Mechanical Engineering, Temple University , Philadelphia, Pennsylvania 19122, United States
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32
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Jankowska J, Sadlej J, Sobolewski AL. Electric field control of proton-transfer molecular switching: molecular dynamics study on salicylidene aniline. Phys Chem Chem Phys 2015; 17:14484-8. [PMID: 25986469 DOI: 10.1039/c5cp00686d] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this letter, we propose a novel, ultrafast, efficient molecular switch whose switching mechanism involves the electric field-driven intramolecular proton transfer. By means of ab initio quantum chemical calculations and on-the-fly dynamics simulations, we examine the switching performance of an isolated salicylidene aniline molecule and analyze the perspectives of its possible use as an electric field-controlled molecular electronics unit.
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Affiliation(s)
- Joanna Jankowska
- College of Interfaculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, 93 Zwirki i Wigury St., 02-089 Warsaw, Poland.
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33
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Zhang Y, Qiao S, Liang S, Wu Z, Yang Z, Feng Z, Sun H, Zhou Y, Sun L, Chen Z, Zou X, Zhang B, Hu J, Li S, Chen Q, Li L, Xu G, Zhao Y, Liu S. Gbps terahertz external modulator based on a composite metamaterial with a double-channel heterostructure. NANO LETTERS 2015; 15:3501-6. [PMID: 25919444 DOI: 10.1021/acs.nanolett.5b00869] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The past few decades have witnessed a substantial increase in terahertz (THz) research. Utilizing THz waves to transmit communication and imaging data has created a high demand for phase and amplitude modulation. However, current active THz devices, including modulators and switches, still cannot meet THz system demands. Double-channel heterostructures, an alternative semiconductor system, can support nanoscale two-dimensional electron gases (2DEGs) with high carrier concentration and mobility and provide a new way to develop active THz devices. In this Letter, we present a composite metamaterial structure that combines an equivalent collective dipolar array with a double-channel heterostructure to obtain an effective, ultrafast, and all-electronic grid-controlled THz modulator. Electrical control allows for resonant mode conversion between two different dipolar resonances in the active device, which significantly improves the modulation speed and depth. This THz modulator is the first to achieve a 1 GHz modulation speed and 85% modulation depth during real-time dynamic tests. Moreover, a 1.19 rad phase shift was realized. A wireless free-space-modulation THz communication system based on this external THz modulator was tested using 0.2 Gbps eye patterns. Therefore, this active composite metamaterial modulator provides a basis for the development of effective and ultrafast dynamic devices for THz wireless communication and imaging systems.
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Affiliation(s)
- Yaxin Zhang
- †Terahertz Science Cooperative Innovation Center, University of Electronic Science and Technology of China, Chengdu 610054, P. R. China
| | - Shen Qiao
- †Terahertz Science Cooperative Innovation Center, University of Electronic Science and Technology of China, Chengdu 610054, P. R. China
| | - Shixiong Liang
- ‡National Key Laboratory of Application Specific Integrated Circuit, Hebei Semiconductor Research Institute, Shijiazhuang 050000, China
| | - Zhenhua Wu
- †Terahertz Science Cooperative Innovation Center, University of Electronic Science and Technology of China, Chengdu 610054, P. R. China
| | - Ziqiang Yang
- †Terahertz Science Cooperative Innovation Center, University of Electronic Science and Technology of China, Chengdu 610054, P. R. China
| | - Zhihong Feng
- ‡National Key Laboratory of Application Specific Integrated Circuit, Hebei Semiconductor Research Institute, Shijiazhuang 050000, China
| | - Han Sun
- †Terahertz Science Cooperative Innovation Center, University of Electronic Science and Technology of China, Chengdu 610054, P. R. China
| | - Yucong Zhou
- †Terahertz Science Cooperative Innovation Center, University of Electronic Science and Technology of China, Chengdu 610054, P. R. China
| | - Linlin Sun
- †Terahertz Science Cooperative Innovation Center, University of Electronic Science and Technology of China, Chengdu 610054, P. R. China
| | - Zhi Chen
- §National Key Laboratory of Communication, University of Electronic Science and Technology of China, Chengdu 610054, P. R. China
| | - Xianbing Zou
- §National Key Laboratory of Communication, University of Electronic Science and Technology of China, Chengdu 610054, P. R. China
| | - Bo Zhang
- ∥School of Electronics Engineering, University of Electronic Science and Technology of China, Chengdu 610054, P. R. China
| | - Jianhao Hu
- §National Key Laboratory of Communication, University of Electronic Science and Technology of China, Chengdu 610054, P. R. China
| | - Shaoqian Li
- §National Key Laboratory of Communication, University of Electronic Science and Technology of China, Chengdu 610054, P. R. China
| | - Qin Chen
- ⊥Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou 215123, P. R. China
| | - Ling Li
- †Terahertz Science Cooperative Innovation Center, University of Electronic Science and Technology of China, Chengdu 610054, P. R. China
| | - Gaiqi Xu
- †Terahertz Science Cooperative Innovation Center, University of Electronic Science and Technology of China, Chengdu 610054, P. R. China
| | - Yuncheng Zhao
- †Terahertz Science Cooperative Innovation Center, University of Electronic Science and Technology of China, Chengdu 610054, P. R. China
| | - Shenggang Liu
- †Terahertz Science Cooperative Innovation Center, University of Electronic Science and Technology of China, Chengdu 610054, P. R. China
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34
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Yoshioka K, Minami Y, Shudo KI, Dao TD, Nagao T, Kitajima M, Takeda J, Katayama I. Terahertz-field-induced nonlinear electron delocalization in Au nanostructures. NANO LETTERS 2015; 15:1036-1040. [PMID: 25559640 DOI: 10.1021/nl503916t] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Improved control over the electromagnetic properties of metal nanostructures is indispensable for the development of next-generation integrated nanocircuits and plasmonic devices. The use of terahertz (THz)-field-induced nonlinearity is a promising approach to controlling local electromagnetic properties. Here, we demonstrate how intense THz electric fields can be used to modulate electron delocalization in percolated gold (Au) nanostructures on a picosecond time scale. We prepared both isolated and percolated Au nanostructures deposited on high resistivity Si(100) substrates. With increasing the applied THz electric fields, large opacity in the THz transmission spectra takes place in the percolated nanostructures; the maximum THz-field-induced transmittance difference, 50% more, is reached just above the percolation threshold thickness. Fitting the experimental data to a Drude-Smith model, we found furthermore that the localization parameter and the damping constant strongly depend on the applied THz-field strength. These results show that ultrafast nonlinear electron delocalization proceeds via strong electric field of THz pulses; the intense THz electric field modulates the backscattering rate of localized electrons and induces electron tunneling between Au nanostructures across the narrow insulating bridges without any material breakdown.
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Affiliation(s)
- Katsumasa Yoshioka
- Department of Physics, Graduate School of Engineering, Yokohama National University , Yokohama 240-8501, Japan
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35
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Osako T, Torii K, Uozumi Y. Aerobic flow oxidation of alcohols in water catalyzed by platinum nanoparticles dispersed in an amphiphilic polymer. RSC Adv 2015. [DOI: 10.1039/c4ra14947e] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Various alcohols were aerobically oxidized in an aqueous solution in a continuous-flow reactor containing a platinum nanoparticles dispersed in a polystyrene–poly(ethylene glycol) resin to give the corresponding carbonyl compounds in up to 99% yield.
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Affiliation(s)
- Takao Osako
- Institute for Molecular Science (IMS) Myodaiji
- Okazaki
- Japan
| | - Kaoru Torii
- Institute for Molecular Science (IMS) Myodaiji
- Okazaki
- Japan
| | - Yasuhiro Uozumi
- Institute for Molecular Science (IMS) Myodaiji
- Okazaki
- Japan
- RIKEN
- Wako
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36
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Baranyai P, Marsi G, Jobbágy C, Domján A, Oláh L, Deák A. Mechano-induced reversible colour and luminescence switching of a gold(i)–diphosphine complex. Dalton Trans 2015; 44:13455-9. [DOI: 10.1039/c5dt01795e] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A gold(i)–diphosphine exhibits an intriguing dual-response (mechanochromism and mechanochromic luminescence) to mechanical stress as a consequence of the reversible neutral-to-ionic phase transition.
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Affiliation(s)
- Péter Baranyai
- Hungarian Academy of Sciences
- MTA TTK SZKI
- “Lendület” Supramolecular Chemistry Research Group
- Magyar Tudósok körútja 2
- Hungary
| | - Gábor Marsi
- Hungarian Academy of Sciences
- MTA TTK SZKI
- “Lendület” Supramolecular Chemistry Research Group
- Magyar Tudósok körútja 2
- Hungary
| | - Csaba Jobbágy
- Hungarian Academy of Sciences
- MTA TTK SZKI
- “Lendület” Supramolecular Chemistry Research Group
- Magyar Tudósok körútja 2
- Hungary
| | - Attila Domján
- Hungarian Academy of Sciences
- MTA TTK SZKI
- NMR Research Group
- Magyar Tudósok körútja 2
- Hungary
| | - Laura Oláh
- Hungarian Academy of Sciences
- MTA TTK SZKI
- “Lendület” Supramolecular Chemistry Research Group
- Magyar Tudósok körútja 2
- Hungary
| | - Andrea Deák
- Hungarian Academy of Sciences
- MTA TTK SZKI
- “Lendület” Supramolecular Chemistry Research Group
- Magyar Tudósok körútja 2
- Hungary
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37
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Ishihara S. Electronic ferroelectricity in molecular organic crystals. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:493201. [PMID: 25398158 DOI: 10.1088/0953-8984/26/49/493201] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Electronic ferroelectricity in molecular organic crystals is reviewed from a theoretical perspective. In particular, we focus on the charge-driven-type electronic ferroelectricity where electronic charge order without inversion symmetry induces a spontaneous electric polarization in quarter-filling systems. Two necessary conditions to realize this type of ferroelectricity are the dimer-type lattice structure and alternate electronic charge alignments. Some prototypical organic compounds are introduced. In particular, κ-type BEDT-TTF organic salts, which are termed the dimer-Mott insulating systems, are focused on. Recent developments in the theoretical researches for dielectric and magnetodielectric properties, a collective dipole excitation and a possibility of superconductivity induced by polar charge fluctuation are reviewed. Some perspectives are presented.
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Affiliation(s)
- Sumio Ishihara
- Department of Physics, Tohoku University, Sendai 980-8578, Japan CREST, Sendai 980-8578, Japan
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38
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D'Avino G, Verstraete MJ. Are hydrogen-bonded charge transfer crystals room temperature ferroelectrics? PHYSICAL REVIEW LETTERS 2014; 113:237602. [PMID: 25526158 DOI: 10.1103/physrevlett.113.237602] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Indexed: 06/04/2023]
Abstract
We present a theoretical investigation of the anomalous ferroelectricity of mixed-stack charge transfer molecular crystals, based on the Peierls-Hubbard model, and first-principles calculations for its parametrization. This approach is first validated by reproducing the temperature-induced transition and the electronic polarization of TTF-CA, and then applied to a novel series of hydrogen-bonded crystals, for which room temperature ferroelectricity has recently been claimed. Our analysis shows that the hydrogen-bonded systems present a very low degree of charge transfer and hence support a very small polarization. A critical reexamination of experimental data supports our findings, shedding doubts on the ferroelectricity of these systems. More generally, our modeling allows the rationalization of general features of the ferroelectric transition in charge transfer crystals and suggests design principles for materials optimization.
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Affiliation(s)
- Gabriele D'Avino
- Université de Liège, Institut de Physique, and European Theoretical Spectroscopy Facility, Allée du 6 Août 17, Sart-Tilman, B-4000 Liège, Belgium
| | - Matthieu J Verstraete
- Université de Liège, Institut de Physique, and European Theoretical Spectroscopy Facility, Allée du 6 Août 17, Sart-Tilman, B-4000 Liège, Belgium
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39
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Yang F, Liu Y, Martha SK, Wu Z, Andrews JC, Ice GE, Pianetta P, Nanda J. Nanoscale morphological and chemical changes of high voltage lithium-manganese rich NMC composite cathodes with cycling. NANO LETTERS 2014; 14:4334-41. [PMID: 25054780 PMCID: PMC4134180 DOI: 10.1021/nl502090z] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 07/10/2014] [Indexed: 05/26/2023]
Abstract
Understanding the evolution of chemical composition and morphology of battery materials during electrochemical cycling is fundamental to extending battery cycle life and ensuring safety. This is particularly true for the much debated high energy density (high voltage) lithium-manganese rich cathode material of composition Li(1 + x)M(1 - x)O2 (M = Mn, Co, Ni). In this study we combine full-field transmission X-ray microscopy (TXM) with X-ray absorption near edge structure (XANES) to spatially resolve changes in chemical phase, oxidation state, and morphology within a high voltage cathode having nominal composition Li1.2Mn0.525Ni0.175Co0.1O2. Nanoscale microscopy with chemical/elemental sensitivity provides direct quantitative visualization of the cathode, and insights into failure. Single-pixel (∼ 30 nm) TXM XANES revealed changes in Mn chemistry with cycling, possibly to a spinel conformation and likely including some Mn(II), starting at the particle surface and proceeding inward. Morphological analysis of the particles revealed, with high resolution and statistical sampling, that the majority of particles adopted nonspherical shapes after 200 cycles. Multiple-energy tomography showed a more homogeneous association of transition metals in the pristine particle, which segregate significantly with cycling. Depletion of transition metals at the cathode surface occurs after just one cycle, likely driven by electrochemical reactions at the surface.
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Affiliation(s)
- Feifei Yang
- National
Synchrotron Radiation Laboratory, University
of Science & Technology of China, Hefei, Anhui 230027, China
| | - Yijin Liu
- Stanford
Synchrotron Radiation Lightsource, SLAC
National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Surendra K. Martha
- Materials
Science & Technology Division, Oak Ridge
National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Ziyu Wu
- National
Synchrotron Radiation Laboratory, University
of Science & Technology of China, Hefei, Anhui 230027, China
| | - Joy C. Andrews
- Stanford
Synchrotron Radiation Lightsource, SLAC
National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Gene E. Ice
- Materials
Science & Technology Division, Oak Ridge
National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Piero Pianetta
- Stanford
Synchrotron Radiation Lightsource, SLAC
National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Jagjit Nanda
- Materials
Science & Technology Division, Oak Ridge
National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department
of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville Tennessee 37996, United States
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