2020 Fiscal Year Annual Research Report
Metal-directed asymmetric spatial assembly of diverse building blocks - spheres, planes, and bowls
Publicly Offered Research
| Project Area | Coordination Asymmetry: Design of Asymmetric Coordination Sphere and Anisotropic Assembly for the Creation of Functional Molecules |
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| Project/Area Number |
19H04590
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| Research Institution | Osaka Prefecture University |
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Principal Investigator |
プラシデス コスマス 大阪府立大学, 工学(系)研究科(研究院), 教授 (90719006)
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| Project Period (FY) |
2019-04-01 – 2021-03-31
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| Keywords | mixed valence / valence transitions / spin frustration / rare earths / fullerides |
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| Outline of Annual Research Achievements |
Research focused on asymmetrically coordinated (cationogenic and anionogenic) mixed valence molecular solids. Progress was achieved in producing magnetically frustrated spin assemblies and driving insulator-to-metal transitions by valence transitions via the application of external stimuli.
[1] The electronic properties of d- and f-shell materials have drawn the bulk of research attention but although unconventional p-electron-based electronic, magnetic and conducting materials are rare, they are a fascinating topic. Among alkali oxides, the molecular sesquioxides A4O6 (A = alkali metal) are of special interest as they are rare examples of binary ionic compounds with molecular dioxygen in two different oxidation states. Our work has unveiled a complex cubic (charge-disordered) to tetragonal (charge-ordered) stability phase space as a function of temperature and pressure together with an intimate link between the lattice geometry and the absence of long-range magnetic ordering, which is
suppressed because of geometric frustration.
[2] Rare-earth (RE) fullerides are an intriguing family of materials in which RE electronic instabilities couple to the electronic and lattice degrees-of-freedom of the strongly-correlated C60 sublattice. We revealed that the asymmetrically-coordinated mixed-valency (Sm1-xCax)2.75C60 materials show pressure-driven reversible phase transitions accompanied by drastic increases in Sm valence and C60 oxidation state. These are coincident with huge lattice contractions and concomitant insulator-to-metal transitions.
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| Research Progress Status |
令和2年度が最終年度であるため、記入しない。
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| Strategy for Future Research Activity |
令和2年度が最終年度であるため、記入しない。
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