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Ogino M, Okamura Y, Fujiwara K, Morimoto T, Nagaosa N, Kaneko Y, Tokura Y, Takahashi Y. Terahertz photon to dc current conversion via magnetic excitations of multiferroics. Nat Commun 2024; 15:4699. [PMID: 38844471 PMCID: PMC11156647 DOI: 10.1038/s41467-024-49056-9] [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: 04/05/2024] [Accepted: 05/23/2024] [Indexed: 06/09/2024] Open
Abstract
Direct conversion from terahertz photon to charge current is a key phenomenon for terahertz photonics. Quantum geometrical description of optical processes in crystalline solids predicts existence of field-unbiased dc photocurrent arising from terahertz-light generation of magnetic excitations in multiferroics, potentially leading to fast and energy-efficient terahertz devices. Here, we demonstrate the dc charge current generation from terahertz magnetic excitations in multiferroic perovskite manganites with spin-driven ferroelectricity, while keeping an insulating state with no free carrier. It is also revealed that electromagnon, which ranges sub-terahertz to 2 THz, as well as antiferromagnetic resonance shows the giant conversion efficiency. Polar asymmetry induced by the cycloidal spin order gives rise to this terahertz-photon-induced dc photocurrent, and no external magnetic and electric bias field are required for this conversion process. The observed phenomena are beyond the conventional photovoltaics in semi-classical regime and demonstrate the essential role of quantum geometrical aspect in low-energy optical processes. Our finding establishes a paradigm of terahertz photovoltaic phenomena, paving a way for terahertz photonic devices and energy harvesting.
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Affiliation(s)
- Makiko Ogino
- Department of Applied Physics and Quantum Phase Electronics Center, University of Tokyo, Tokyo, Japan
| | - Yoshihiro Okamura
- Department of Applied Physics and Quantum Phase Electronics Center, University of Tokyo, Tokyo, Japan
| | - Kosuke Fujiwara
- Department of Applied Physics and Quantum Phase Electronics Center, University of Tokyo, Tokyo, Japan
| | - Takahiro Morimoto
- Department of Applied Physics and Quantum Phase Electronics Center, University of Tokyo, Tokyo, Japan
| | - Naoto Nagaosa
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Japan
| | - Yoshio Kaneko
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Japan
| | - Yoshinori Tokura
- Department of Applied Physics and Quantum Phase Electronics Center, University of Tokyo, Tokyo, Japan
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Japan
- Tokyo College, University of Tokyo, Tokyo, Japan
| | - Youtarou Takahashi
- Department of Applied Physics and Quantum Phase Electronics Center, University of Tokyo, Tokyo, Japan.
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Japan.
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Microwave-Assisted Photocatalytic Degradation of Organic Pollutants via CNTs/TiO2. Catalysts 2022. [DOI: 10.3390/catal12090940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Introducing microwave fields into photocatalytic technology is a promising strategy to suppress the recombination of photogenerated charge carriers. Here, a series of microwave-absorbing photocatalysts, xCNTs/TiO2, were prepared by combining titanium dioxide (TiO2) with carbon nanotubes (CNTs) using a typical alcoholic thermal method to study the promotion of microwave-generated thermal and athermal effects on the photocatalytic oxidation process. As good carriers that are capable of absorbing microwaves and conducting electrons, CNTs can form hot spots and defects under the action of the thermal effect from microwaves to capture electrons generated on the surface of TiO2 and enhance the separation efficiency of photogenerated electrons (e−) and holes (h+). Excluding the influence of the reaction temperature, the athermal effect of the microwave field had a polarizing effect on the catalyst, which improved the light absorption rate of the catalyst. Moreover, microwave radiation also promoted the activation of oxygen molecules and hydroxyl groups on the catalyst surface to generate more reactive oxygen radicals. According to the mechanism analysis, the microwave effect significantly improved the photocatalytic advanced oxidation process, which lays a solid theoretical foundation for practical application.
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Taniguchi K, Nishio M, Abe N, Huang PJ, Kimura S, Arima TH, Miyasaka H. Magneto-Electric Directional Anisotropy in Polar Soft Ferromagnets of Two-Dimensional Organic-Inorganic Hybrid Perovskites. Angew Chem Int Ed Engl 2021; 60:14350-14354. [PMID: 33886136 DOI: 10.1002/anie.202103121] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 04/06/2021] [Indexed: 12/12/2022]
Abstract
Two-dimensional organic-inorganic hybrid perovskites (2D-OIHPs) are attracting interest due to their structural tunability and rich functional characteristics, such as ferroelectricity and ferromagnetism. Here, we report the chiral-polar ferromagnetic 2D-OIHP copper chlorides with discernable electric polarization in the inorganic layers. In these systems, the magneto-electric (ME) correlation has been clearly observed by measuring a magneto-electric directional anisotropy (MEA), in which an optical absorption coefficient changes with reversal of the light propagating direction. We have found that the MEA can be induced by a low magnetic field of about 50 mT, reflecting soft magnetic nature. The present results suggest a new paradigm for designing functional ME multiferroics, which effectively couples magnetic and electric properties.
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Affiliation(s)
- Kouji Taniguchi
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan.,PRESTO, Japan Science and Technology Agency (JST), 5-3 Yonbancho, Chiyoda-ku, Tokyo, 102-8666, Japan.,Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-ku, Sendai, 980-8578, Japan
| | - Masaki Nishio
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
| | - Nobuyuki Abe
- Department of Advanced Materials Science, The University of Tokyo, 5-1-5 Kashiwa, Chiba, 277-8561, Japan
| | - Po-Jung Huang
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-ku, Sendai, 980-8578, Japan
| | - Shojiro Kimura
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
| | - Taka-Hisa Arima
- Department of Advanced Materials Science, The University of Tokyo, 5-1-5 Kashiwa, Chiba, 277-8561, Japan
| | - Hitoshi Miyasaka
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan.,Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-ku, Sendai, 980-8578, Japan
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Taniguchi K, Nishio M, Abe N, Huang P, Kimura S, Arima T, Miyasaka H. Magneto‐Electric Directional Anisotropy in Polar Soft Ferromagnets of Two‐Dimensional Organic–Inorganic Hybrid Perovskites. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202103121] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Kouji Taniguchi
- Institute for Materials Research Tohoku University 2-1-1 Katahira Aoba-ku Sendai 980-8577 Japan
- PRESTO Japan Science and Technology Agency (JST) 5-3 Yonbancho, Chiyoda-ku Tokyo 102-8666 Japan
- Department of Chemistry Graduate School of Science Tohoku University 6-3 Aramaki-Aza-Aoba Aoba-ku Sendai 980-8578 Japan
| | - Masaki Nishio
- Institute for Materials Research Tohoku University 2-1-1 Katahira Aoba-ku Sendai 980-8577 Japan
| | - Nobuyuki Abe
- Department of Advanced Materials Science The University of Tokyo 5-1-5 Kashiwa Chiba 277-8561 Japan
| | - Po‐Jung Huang
- Department of Chemistry Graduate School of Science Tohoku University 6-3 Aramaki-Aza-Aoba Aoba-ku Sendai 980-8578 Japan
| | - Shojiro Kimura
- Institute for Materials Research Tohoku University 2-1-1 Katahira Aoba-ku Sendai 980-8577 Japan
| | - Taka‐hisa Arima
- Department of Advanced Materials Science The University of Tokyo 5-1-5 Kashiwa Chiba 277-8561 Japan
| | - Hitoshi Miyasaka
- Institute for Materials Research Tohoku University 2-1-1 Katahira Aoba-ku Sendai 980-8577 Japan
- Department of Chemistry Graduate School of Science Tohoku University 6-3 Aramaki-Aza-Aoba Aoba-ku Sendai 980-8578 Japan
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Kimura S, Matsumoto M, Tanaka H. Electrical Switching of the Nonreciprocal Directional Microwave Response in a Triplon Bose-Einstein Condensate. PHYSICAL REVIEW LETTERS 2020; 124:217401. [PMID: 32530678 DOI: 10.1103/physrevlett.124.217401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 04/09/2020] [Accepted: 04/29/2020] [Indexed: 06/11/2023]
Abstract
We present a microwave electron spin resonance study of the quantum spin dimer system TlCuCl_{3}, which shows the magnetic-field-induced ordering with both antiferromagnetic spin order and ferroelectricity by the Bose-Einstein condensation (BEC) of triplon quasiparticles. Our main achievement is an electrical switching of the nonreciprocal directional microwave response in the triplon BEC phase. High-speed directional control of microwave absorption by applying an electric field has been accomplished in this Letter. The strength of the observed nonreciprocal microwave response well agrees with the calculation based on Kubo theory with the parameters, evaluated from the static electric polarization in this material.
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Affiliation(s)
- Shojiro Kimura
- Institute for Materials Research, Tohoku University, Katahira 2-1-1, Sendai 980-8577, Japan
| | | | - Hidekazu Tanaka
- Department of Physics, Tokyo Institute of Technology, Tokyo 152-8551, Japan
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Lu C, Wu M, Lin L, Liu JM. Single-phase multiferroics: new materials, phenomena, and physics. Natl Sci Rev 2019; 6:653-668. [PMID: 34691921 PMCID: PMC8291614 DOI: 10.1093/nsr/nwz091] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 06/15/2019] [Accepted: 06/20/2019] [Indexed: 12/23/2022] Open
Abstract
Multiferroics, where multiple ferroic orders coexist and are intimately coupled, promise novel applications in conceptually new devices on one hand, and on the other hand provide fascinating physics that is distinctly different from the physics of high-TC superconductors and colossal magnetoresistance manganites. In this mini-review, we highlight the recent progress of single-phase multiferroics in the exploration of new materials, efficient roadmaps for functionality enhancement, new phenomena beyond magnetoelectric coupling, and underlying novel physics. In the meantime, a slightly more detailed description is given of several multiferroics with ferrimagnetic orders and double-layered perovskite structure and also of recently emerging 2D multiferroics. Some emergent phenomena such as topological vortex domain structure, non-reciprocal response, and hybrid mechanisms for multiferroicity engineering and magnetoelectric coupling in various types of multiferroics will be briefly reviewed.
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Affiliation(s)
- Chengliang Lu
- School of Physics & Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Menghao Wu
- School of Physics & Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Lin Lin
- Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China
| | - Jun-Ming Liu
- Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China
- Institute for Advanced Materials, Hubei Normal University, Huangshi 435002, China
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Okamura Y, Seki S, Bordács S, Butykai Á, Tsurkan V, Kézsmárki I, Tokura Y. Microwave Directional Dichroism Resonant with Spin Excitations in the Polar Ferromagnet GaV_{4}S_{8}. PHYSICAL REVIEW LETTERS 2019; 122:057202. [PMID: 30822005 DOI: 10.1103/physrevlett.122.057202] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Indexed: 06/09/2023]
Abstract
We have investigated the directional dichroism of magnetic resonance spectra in the polar ferromagnet GaV_{4}S_{8}. While four types of structural domains are energetically degenerated under a zero field, the magnetic resonance for each domain is well separated by applying magnetic fields due to uniaxial magnetic anisotropy. Consequently, a directional dichroism as large as 20% is clearly observed without domain cancellation. The present observation therefore demonstrates that not only magnetoelectric monodomain crystals but also magnetoelectric multidomain specimens can be used to realize microwave (optical) diodes owing to the lack of inversion domains.
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Affiliation(s)
- Y Okamura
- Department of Applied Physics and Quantum Phase Electronics Center, University of Tokyo, Tokyo 113-8656, Japan
| | - S Seki
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - S Bordács
- Department of Physics, Budapest University of Technology and Economics and MTA-BME Lendulet Magneto-optical Spectroscopy Research Group, 1111 Budapest, Hungary
- Hungarian Academy of Sciences, Premium Postdoctor Program, 1051 Budapest, Hungary
| | - Á Butykai
- Department of Physics, Budapest University of Technology and Economics and MTA-BME Lendulet Magneto-optical Spectroscopy Research Group, 1111 Budapest, Hungary
| | - V Tsurkan
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159 Augsburg, Germany
| | - I Kézsmárki
- Department of Physics, Budapest University of Technology and Economics and MTA-BME Lendulet Magneto-optical Spectroscopy Research Group, 1111 Budapest, Hungary
| | - Y Tokura
- Department of Applied Physics and Quantum Phase Electronics Center, University of Tokyo, Tokyo 113-8656, Japan
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
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