1996 Fiscal Year Final Research Report Summary
Low-dimensional electronic states and electron coorelation in organic conductors
| Project/Area Number |
05402009
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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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Ⅰ(光物性・半導体・誘電体)
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| Research Institution | The University of Tokyo |
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Principal Investigator |
KAGOSHIMA Seiichi The University of Tokyo, Graduate School of Arts and Sciences, Professor, 大学院・総合文化研究科, 教授 (30114432)
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| Co-Investigator(Kenkyū-buntansha) |
SAITO Gunzi Kyoto University, Graduate School of Science, Professor, 大学院・理学研究所, 教授 (40132724)
KATO Reizo The University of Tokyo, Institute for Solid State Physics, Associate Professor, 物性研究所, 助教授 (80169531)
OSADA Toshihito The University of Tokyo, Research Center for Advanced Science and Technology, As, 先端科学技術研究センター, 助教授 (00192526)
WADA Nobuo The University of Tokyo, Graduate School of Arts and Sciences, Associate Profess, 大学院・総合文化研究科, 助教授 (90142687)
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| Project Period (FY) |
1993 – 1996
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| Keywords | organic conductor / low-dimensional electronic system / BEDT-TTF / TMTSF / DCNQI / Peierls transition / Mott transition / Magnetoresistance |
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| Research Abstract |
The purpose of the present research is to clarify characteristic properties of low-dimentional electronic systems in organic conductors in the light of the Coulomb correlation between conduction electrons. Research results are summarized in two points : (1) We established the important role of high magnetic fields in studying low-dimensional electronic properties, and clarified a wide variety of electronic properties caused by the magnetic fields and theoretical basis for these phenomena. (2) We made clear the physical mechanism for a novel metal-insulator transition in some organic conductors.
In the study on one-dimensional electronic properties based on TMTSF molecule it was clarified that various features of magnetoresistance as a function of the angle between the magnetic field direction and the crystalline axis are explained basically by the semi-classical theory based on the band theory and the Boltzman equation. This results gave a common basis for the study on two-dimensional e
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lectronic systems described below. With respect to the possible internal phase structure in the spin-density wave state caused by the one-dimensionality and the electron correlation our original idea to investigate this from the view point of the single particle transport under high magnetic fields revealed that a band structural change caused the change in the electronic structure in the spin-density wave state.
Electronic properties of the two-dimensional systembased on BEDT-TTF molecules were studied by measurements of the angle-dependent magnetoresistance oscillations under high pressures to made clear the origin of the so-called anomalous state appearing at low temperatures. In addition we found the presence of three-dimensionality causes an anomalous increase of magnctoresistance for the magnetic filed close to the conducting plane.
The metal-insulator transition in one-dimensional DCNQI conductors was found to be due to interplay among the Peierls transition of one-dimensional system, the Mott transition of highly correlated system, the Jahn-Teller effect around the copper ion, magnetic spins of copper 2*state and their entropy. Less
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