| Project/Area Number |
14103005
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| Research Category |
Grant-in-Aid for Scientific Research (S)
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| Allocation Type | Single-year Grants |
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| Research Field |
機能・物性・材料
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| Research Institution | The University of Tokyo |
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Principal Investigator |
KOBAYASHI Akiko The University of Tokyo, Research Centre for Spectrochemistry, Graduate School of Science, Professor, 大学院・理学系研究科, 教授 (50011705)
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| Co-Investigator(Kenkyū-buntansha) |
FUJIWARA Emiko The University of Tokyo, Research Centre for Spectrochemistry, Graduate School of Science, Research Assistant, 大学院・理学系研究科, 助手 (30361562)
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| Project Period (FY) |
2002 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥72,020,000 (Direct Cost: ¥55,400,000、Indirect Cost: ¥16,620,000)
Fiscal Year 2005: ¥10,920,000 (Direct Cost: ¥8,400,000、Indirect Cost: ¥2,520,000)
Fiscal Year 2004: ¥11,960,000 (Direct Cost: ¥9,200,000、Indirect Cost: ¥2,760,000)
Fiscal Year 2003: ¥11,960,000 (Direct Cost: ¥9,200,000、Indirect Cost: ¥2,760,000)
Fiscal Year 2002: ¥37,180,000 (Direct Cost: ¥28,600,000、Indirect Cost: ¥8,580,000)
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| Keywords | Single-Component Molecular Metals / Molecular Conductors / Dithiolate Metal Complex / Antiferromagnetic Phase Transition / Molecular Alloy Systems / Three-Dimensional Fermi Surfaces / 中性単一分子性金属 / ジチオレン錯体 / 混晶 / 単一成分分子性金属 / 拡張型ジチオレン錯体 / 粉末X線回折 / ^1HNMR / 電気伝導度 / 第一原理バンド計算 / 電子吸収スペクトル / HOMO-LUMO gap / 拡張型TTF / 中性単一分子 / 中性単一成分分子金属 |
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| Research Abstract |
In this work, in order to realize the single-component metallic molecular magnets and molecular superconductors with various extended-TTF ligands, the structures, physical properties and molecular functions of a series of new developed single-component complexes were investigated.
To obtain direct evidence for the existence of Fermi surfaces in the first neutral metal complex molecule [Ni(tmdt)_2] (tmdt=trimethylenetetrathiafulvalenedithiolate), we have carried out experiments to measure magnetic quantum oscillations, namely de Haas-van Alphen (dHvA) oscillations, in high magnetic fields up to 33 T using a microcantilever. The observation of the dHvA signal in [Ni(tmdt)_2] demonstrates that it is a single-component molecular crystal which not only shows metallic conductivity behavior down to low temperatures, but also exhibits high-quality quantum oscillations characteristic of a Fermi surface. These results unambiguously show the existence of 3D Fermi surfaces for both holes and electr
… More
ons in this molecular crystal.
To create the single-component metallic molecular magnets with a high transition temperature, [Au(tmdt)_2] was developed, which is isostructural to that of [Ni(tmdt)_2]. Unlike the neutral bis (dithiolato) nickel complex, the neutral bis (dithiolato) gold complex has an odd number of total electrons. The spin susceptibilities study of [Au(tmdt)_2] showed an unusual antiferromagnetic phase transition around 110K, which is higher than that of the classical antiferromagnetic metal Mn around 100K. More recently, the metallic behavior down to phase transition temperature was observed by the resistivity measurements on a microcrystal of [Au(tmdt)_2], which indicate that the single-component metallic molecular magnets have been realized.
Since the Fermi surfaces of [Ni(tmdt)_2] are quite different from those of [Au(tmdt)_2], the molecular alloy system will be expected to be the single-component molecular superconductor. We have succeeded to prepare the first "single-component alloy system" [Ni_<1-x>Au_x(tmdt)_2](0<x<1). The resistivity of single crystal of [Ni_<0.75>Au_<0.25>(tmdt)_2] was abruptly deceasing below 2K, and the magnetic susceptibility was also slightly decreasing at the temperature range form 1.8 to 0.8K, which maybe stem from the partially appeared superconducting state. We think the "single-component molecular superconductor" may be realized in such an alloy system. Less
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