2021 Fiscal Year Annual Research Report
Chemistry of open-shell carbon-based pi-electron molecular materials and development into spin liquids
| Project/Area Number |
21H01907
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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) |
2021-04-01 – 2024-03-31
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| Keywords | carbon-based / molecular materials / spin liquids / polyaromatics / fullerenes |
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| Outline of Annual Research Achievements |
The project targets the synthesis of new crystalline materials families whose building blocks are electronically-active π-electron unsaturated organic molecular anions of varying size, shape, and electronic structure. We have been employing the new chemistry we pioneered in recent years to control the positioning of the pi-electron open-shell building blocks in space and create geometrically-frustrated magnetic lattices, which can act as hosts of quantum spin liquids purely arising from carbon pi-electrons. These strongly-correlated Mott insulating phases are further manipulated chemically and physically to turn them into metals and superconductors. Chemical synthesis is combining with high-level theory and integrated with a range of state-of-the-art structural and magnetic measurement techniques to identify the new electronic states that arise. To-date, two key research achievements have been reached: (i) the demonstration of the sensitivity of the fragile magnetic states to small perturbations induced by the chemical dopants that lead to transitions to long-range-ordered magnetic states, and (ii) the incorporation of spherical units like C60 to afford hybrid systems, promising candidates of new metallic and superconducting states.
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| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
Progress has been very satisfactory with new directions and opportunities appearing. Work on pi-electron carbon-based molecular materials has led to families of new materials and new properties are emerging. The wealth of reduced pi-electron families of polyaromatic hydrocarbons chemically synthesized in this work has led to numerous investigations of the fragility of the magnetic states with changes in the nature of the dopant and the modified crystalline structures. In addition, first steps towards synthesizing hybrid pi-electron systems have been successful by incorporating fullerenes into the polyaromatic hydrocarbon architectures. Structural and magnetic characterizations are in progress.
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| Strategy for Future Research Activity |
The behavior of the binary phases of reduced polyaromatic hydrocarbons doped with alkali metals will be investigated by a variety of experimental techniques probing accurately both the changes in crystalline structure and the resulting changes in the magnetic properties. Experimental techniques to be used will be synchrotron X-ray and powder neutron diffraction combined with complementary magnetization, EPR, NMR and muSR measurements. The separate thread of hybrid molecular solids will be extended to include the isolation of reduced phases where the number of injected electrons is accurately controlled. The characterization of the line phases resulting as a result of this chemistry will be attempted at first stage by synchrotron X-ray diffraction and by SQUID magnetometry.
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