2007 Fiscal Year Final Research Report Summary
Direct Observation of Electron Density Distribution of the Molecular Orbital Detected by Synchrotron Radiation X-Pay Diffraction
| Project/Area Number |
18310073
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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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| Research Field |
Nanostructural science
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| Research Institution | High Energy Accelerator Research Organization |
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Principal Investigator |
SAWA Hiroshi High Energy Accelerator Research Organization, Institute of Materials Structure Science, Professor (50215901)
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| Project Period (FY) |
2006 – 2007
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| Keywords | Synchrotron Radiation X-ray / Single Crystal Structure Analysis / Charge Density Analysis / Molecular Conductor / Charge Ordering / Wigner Crystallization / Charge Density Wave |
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| Research Abstract |
The Synchrotron Radiation (SR) X-ray is finding increasing use in the study of material science. In this project, we utilized the SR X-ray diffraction methods for the determination of the electronic state in the novel molecular crystals.
Rarefied electron gas system at high temperature is homogeneous due to the large kinetic energy compared to the Coulomb repulsion among electrons. At extreme low temperatures, the system will tend to condense and make uneven lumps, as theoretically predicted in the early 1930's. Since these lumps carry a negative charge, they form a structure where they try to avoid each other in the spatial positioning. We call this phenomenon the Wigner crystallization. A molecular conductor (DI-DCNQI)_2Ag is insulating even at room temperature. Below 220 K, Hiraki and Kanoda suggested that the 4k_F Wigner crystal type of charge order (CO) on DCNQI molecules by NMR technique. This CO ground state was theoretically predicted by Seo, et. al. It is very interesting whether (or how) the electron crystal is stable in the real solid. Single crystal x-ray diffraction measurements using SR were performed at PF, KEK. According to the result of the structural analysis, two-fold structure in ground state consists of not only charge ordering columns but also monotonic charge dimerized columns caused by geometrical frustration among DCNQI columns. In spite of these complicated order parameters, this charge ordered structure is regarded as a Wigner crystal caused by inter-column Coulomb repulsion. This is a first direct observation of the 3D electron crystal. Furthermore, we investigated the electronic state in several molecular materials during the term of project.
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[Journal Article] Superconductivity of doped Ar@C_<60>2007
Author(s)
K. Yakigaya, A. Takeda, Y. Yokoyama, S. Ito, T. Miyazaki, T. Suetsuna, H. Shimotani, T. Kakiuchi, H. Sawa, H. Takagi, K. Kitagawa, N. Dragoe
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Journal Title
New Journal of Chemistry 31
Pages: 973-979
Description
「研究成果報告書概要(和文)」より
Peer Reviewed
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[Journal Article] Superconductivity of doped AR@C602007
Author(s)
K. Yakigaya, A. Takeda, Y. Yokoyama, S. Ito, T. Miyazaki, T. Suetsuna, H. Shimotani, T. Kakiuchi, H. Sawa, H. Takagi, K. Kitagawa, N. Dragoe
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Journal Title
New Journal of Chemistry 31
Pages: 973-979
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Dynamical Valence Fluctuation at the Charge-Density-Wave Phase Boundary in Iodide-Bridged Pt Compound [Pt(chxn)_2I]I_22006
Author(s)
S. Takaishi, D. Kawakami, M. Yamashita, M. Sasaki, T. Kajiwara, H. Miyasaka, K. Sugiura, Y. Wakabayashi, H. Sawa, H. Matsuzaki, H. Kishida, H. Okamoto, H. Watanabe, H. Tanaka, K. Marumoto, H. Ito, S. Kuroda
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Journal Title
J. Am. Chem. Soc. 128
Pages: 6420-6425
Description
「研究成果報告書概要(和文)」より
Peer Reviewed
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[Journal Article] Halogen-Bridged PtII/PtIV Mixed-Valence Ladder Compounds2006
Author(s)
D. Kawakami, M. Yamashita, S. Matsunaga, S. Takeishi, T. Kajiwara, H. Miyasaka, K. Sugiura, H. Matsuzaki, H. Okamoto, Y. Wakabayashi, H. Sawa
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Journal Title
Angewandte Chemie Int. Ed. 45
Pages: 7214-7217
Description
「研究成果報告書概要(和文)」より
Peer Reviewed
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[Journal Article] Dynamical Valence Fluctuation at the Charge-Density-Wave Phase Boundary in Iodide-Bridged Pt Compound [Pt(chxn) 2I]I22006
Author(s)
S. Takaishi, D. Kawakami, M. Yamashita, M. Sasaki, T. Kajiwara, H. Miyasaka, K. Sugiura, Y. Wakabayashi, H. Sawa, H. Matsuzaki, H. Kishida, H. Okamoto, H. Watanabe, H. Tanaka, K. Marumoto, H. Ito, S. Kuroda
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Journal Title
J. Am. Chem. Soc. 128(19)
Pages: 6420-6425
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Superconducivity of doped Ar@C602006
Author(s)
A. Takeda, Y. Yokoyama, S. Ito, T. Miyazaki, H. Shimotani, K. Yakigaya, T. Kakiuchi, H. Sawa, H. Takagi, K. Kitazawa, N. Dragoe
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Journal Title
Chem. Commun. 8 8
Pages: 912-914
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Halogen-Bridged PtII/PtIV Mixed-Valence Ladder Compounds2006
Author(s)
D. Kawakami, M. Yamashita, -S. Matsunaga, S. Takeishi, T. Kajiwara, H. Miyasaka, K. Sugiura, H. Matsuzaki, H. Okamoto, Y. Wakabayashi, H. Sawa
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Journal Title
Angewandte Chemie Int. Ed. 45
Pages: 7214-7217
Description
「研究成果報告書概要(欧文)」より
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[Presentation] Structural Study of MgB_2-type Superconductor CaAlSi using SR X-ray and TOF-Neutron Diffraction Methods Diffraction Methods2006
Author(s)
H. Sawa, Y. Wakabayashi, T. Kamiyama, H. Sagayama, A. Hoshikawa, S. Harjo, K. Uozato, A. K. Ghosh, M. Tokunaga, T. Tamegai, S. Kuroiwa, J. Akimitsu
Organizer
The 1st International Symposium of Quantum Beam Science directorate of JAEA
Place of Presentation
Tokaimura, Japan
Year and Date
20060828-30
Description
「研究成果報告書概要(欧文)」より
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[Presentation] Structural Study of MgB_2-type Superconductor Ca(Al1/2Si1/2) 22006
Author(s)
H. Sawa, Y. Wakabayashi, T. Kamiyama, H. Sagayama, A. Hoshikawa, S. Harjo, K. Uozato, A. K. Ghosh, M. Tokunaga, T. Tamegai, S. Kuroiwa, J. Akimitsu
Organizer
The International Symposium on Anomalous Quantum Materials 2006 and the 5th Asia-Pacific Workshop
Place of Presentation
Okinawa, Japan
Year and Date
20060123-27
Description
「研究成果報告書概要(欧文)」より
