Novel quantum properties and lattice dynamics caused by suppression of ferroelectricity
| Project/Area Number |
20H01844
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Review Section |
Basic Section 13020:Semiconductors, optical properties of condensed matter and atomic physics-related
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| Research Institution | Osaka Metropolitan University (2022)
Osaka Prefecture University (2020-2021) |
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Principal Investigator |
Ishii Yui 大阪公立大学, 大学院工学研究科, 准教授 (50708013)
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Project Status |
Completed (Fiscal Year 2022)
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| Budget Amount *help |
¥17,940,000 (Direct Cost: ¥13,800,000、Indirect Cost: ¥4,140,000)
Fiscal Year 2022: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Fiscal Year 2021: ¥8,190,000 (Direct Cost: ¥6,300,000、Indirect Cost: ¥1,890,000)
Fiscal Year 2020: ¥7,800,000 (Direct Cost: ¥6,000,000、Indirect Cost: ¥1,800,000)
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| Keywords | 構造量子臨界点 / ソフトモード / ソフトフォノン / フォノン / 構造相転移 / 量子臨界点 / 強誘電体 |
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| Outline of Research at the Start |
本研究では、(a)BaAl2O4間接型強誘電体が示す強誘電的揺らぎに起因した、新奇フォノン物性を開拓するとともに、(b)非弾性X線散乱、非弾性中性子散乱、PDF解析などの散乱手法を用いて、この強誘電的な揺らぎに起因したdisorder状態での格子ダイナミクスを解明する。これに加え、(c)直接型・間接型強誘電体それぞれに対し、強誘電性の抑制に伴う物性変化を系統的に調べることで、強誘電体の量子物性の開拓とそのミクロスコピックな解明を行い、「強誘電的揺らぎがもたらす物理」の学理基盤を築く。
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| Outline of Final Research Achievements |
In this project, we have revealed that a “sublattice glass state” appears at the structural quantum critical point where an acoustic-phonon-driven structural phase transition is suppressed down to the absolute zero temperature. This state possesses both crystalline periodicity and glasslike atomic arrangement. As a result of the glasslike atomic arrangement, the lattice-specific heat shows an excess approximately at 10 K and a T-linear term at the lowest temperatures, and the thermal conductivity shows a plateau, all of which are the typical characteristics of amorphous solids. In addition, it was found that the atomic vibrational state of this state resembles that amorphous solids typically exhibit.
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| Academic Significance and Societal Importance of the Research Achievements |
量子臨界点の研究はこれまで磁気秩序などスピンのかかわる秩序相を対象として発展し、それに隣接して現れる新奇量子相の研究は、今日に至るまで物性物理学の一大分野を築いている。しかしながら、スピンと並びフォノンも固体中の基本的な量子の1つであるにもかかわらず、フォノンが主役となって現れる量子臨界点の研究はほとんど進んで来なかった。本研究で得られた成果は、従来のスピン主体の量子臨界研究をフォノン系に展開するための足がかりとなると期待できる。
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Report
(4 results)
Research Products
(20 results)
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[Journal Article] Lone-Pair-Induced Intra-and Interlayer Polarizations in Sillen-Aurivillius Layered Perovskite Bi4NbO8Br2022
Author(s)
Zhong C, Ishii Y, Tassel C, Zhu T, Kato D, Kurushima K, Fujibayashi Y, Saito T, Ogawa T, Kuwabara A, Mori S, Kageyama H
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Journal Title
Inorganic chemistry
Volume: 61
Issue: 25
Pages: 9816-9822
DOI
Related Report
Peer Reviewed
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[Journal Article] Structural phase transition in cobalt oxyfluoride Co3Sb4O6F6 observed by high-resolution synchrotron and neutron diffraction2021
Author(s)
S. Shimono, H. Ishibashi, Y. Nagayoshi, H. Ikeno, S. Kawaguchi, M. Hagihala, S. Torii, T. Kamiyama, K. Ichihashi, S. Nishihara, K. Inoue, Y. Ishii, Y. Kubota
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Journal Title
Journal of Physics and Chemistry of Solids
Volume: 163
Pages: 110568-110568
DOI
Related Report
Peer Reviewed / Int'l Joint Research
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[Presentation] Spin reorientation in layered perovskite oxyfluoride Pb3Fe2O5F22021
Author(s)
K. Oka, Y. Nambu, M. Ochi, N. Hayashi, Y. Kusano, T. Aoyama, Y. Ishii, K. Kuroki, S. Mori, M. Takano, N. Noma, M. Iwasaki and H. Kageyama
Organizer
International Conference on Mixed-Anion Compounds
Related Report
Int'l Joint Research / Invited
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