| Project/Area Number |
11640362
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
固体物性Ⅱ(磁性・金属・低温)
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| Research Institution | Osaka University (2000-2001)
Okazaki National Research Institutes (1999) |
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Principal Investigator |
NAKAZAWA Yasuhiro Osaka University, Graduate school of Science, Research Associate, 大学院・理学研究科, 助手 (60222163)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 2000: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1999: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Keywords | Electron Correlation / Mott Transition / Charge Order / Heat Capacity / 電子相関効果 / 低温電子比熱 |
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| Research Abstract |
This project is proposed to establish a systematic understanding of the various type of insulation mechanism due to electron correlation effects, which appears in organic 2 : 1salts consisting of BEDT-TTF and DCNQI molecules. Throughout the project, we tried to see the nature of the ground state and low-energy excitations from it by means of the thermodynamic measurements.
In the fiscal year 1999, we focussed on studying the peculiar properties around the Mott boundary in the phase diagram of κ-(BEDT-TTF)_2X system. Using the chemical pressure effect produed by partial deuteration in BEDT-TTF molecules, we have got the information on the variation of γ-term across the Mott boundary for the first time. The γvalue decrease monotonously with approaching the insulating phase and no Brinkmann-Rice type enhancement was observed. The psuedo-gap picture established in high-Tc oxide seems to be favored in this system.
Next year, we have dealt with the non-dimeric quasi-one-dimensional system (DI-DCNQI)_2Ag in terms of charge-ordering due to the long-range Coulomb interaction, V. Although we could not find any thermal anomaly around the charge-order transition, the existence of large one-dimensional spin excitations which is sensitively suppressed by external magnetic fields has been observed. The possibility of field induced spin-gap is suggested in this system.
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