| Project/Area Number |
17340099
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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 |
Condensed matter physics II
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| Research Institution | Tohoku University |
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Principal Investigator |
SASAKI Takahiko Tohoku University, Institute for Materials Research Tohoku University, Associate Professor (20241565)
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| Co-Investigator(Kenkyū-buntansha) |
YONEYAMA Naoki Institute for Materials Research, 金属材料研究所, Assistant Professor (80312643)
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| Project Period (FY) |
2005 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥16,400,000 (Direct Cost: ¥15,500,000、Indirect Cost: ¥900,000)
Fiscal Year 2007: ¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000)
Fiscal Year 2006: ¥5,200,000 (Direct Cost: ¥5,200,000)
Fiscal Year 2005: ¥7,300,000 (Direct Cost: ¥7,300,000)
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| Keywords | organic conductors / highly correlated electrons / phase separation / optical properties / carrier doping / Mott insulator / モット転移 / 赤外分光 / 分子振動 / 相転移 |
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| Research Abstract |
The purpose of this research is the understanding of the intrinsic inhomogeneous electronic states appeared nearby the Mott insulator- metal transition in the highly correlated organic molecular system. The real space imaging of the inhomogeneous phase separation of the Mott insulator and the correlated metal was obtained by means of the scanning micro-region infrared spectroscopy (SMIS) using synchrotron radiation. The achievements in this research project are listed below
1. We clarified the origin of the electronic phase separation nearby the Mott insulator-metal transition in the organic Mott system whose bandwidth was finely controlled by the molecular substitution. The growth condition and pattern of the phase separation were obtained by SMIS measurements.
2. We hound that the microscopic electronic phase separation was closely related to the macroscopic phenomena like as the transport properties. We investigated the relationship between electrical resistivity and the phase separat
… More
ion.
3. Charge order transition was investigated by means of the scanning tunnel microscopy. We observed the real space charge order pattern in the molecular scale resolution by STM.
4. We found large reduction of the superconducting transition temperature Tc by introducing the non-magnetic impurities. At the same time, the scattering time of the quasi-particles became short. The relation between Tc and scattering time indicated the non-BCS type superconductivity in the organic superconductors.
5. We found the competitive relation between the superconductivity and Mott insulator phases in the organic Mott system. Under magnetic fields, the superconductivity was suppressed but the Mott insulator phase spread.
6. We discovered the effective carrier doping to the Mott insulator by the X-ray irradiation. X-ray irradiation introduced the molecular defects in the crystal. Charge transfer between donor and acceptor molecules was modulated locally and the effective carrier doping took place. It is the first success of the controllable carrier doping to the BEDT-TTF molecule based organic conductors. Less
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