| Project/Area Number |
10440103
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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 |
固体物性Ⅱ(磁性・金属・低温)
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| Research Institution | UNIVERSITY OF TOKYO |
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Principal Investigator |
TAKAGI Hidenori UNIVERSITY OF TOKYO, GRADUATE SCHOOL OF FRONTIER SCIENCES, PROFESSOR, 大学院・新領域創成科学研究科, 教授 (40187935)
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| Co-Investigator(Kenkyū-buntansha) |
NOHARA Minoru UNIVERSITY OF TOKYO, GRADUATE SCHOOL OF FRONTIER SCIENCES, ASSOCIATE PROFESSOR, 大学院・新領域科学研究科, 助教授 (70272531)
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| Project Period (FY) |
1998 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥6,200,000 (Direct Cost: ¥6,200,000)
Fiscal Year 2000: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1999: ¥4,800,000 (Direct Cost: ¥4,800,000)
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| Keywords | one dimensional chain / Tomonaga Luttinger liquid / magnetic field induced dimensional crossover / Y1248 / spin liquid / geometrical frustration / スピネル酸化物 / YBa CuO / 結晶成長 / 朝永-ラッティンジャー / YBa_2 Cu_4 O_8 / 強相関一次元電子系 / YBa_2Cu_4O_8 / 磁場誘起次元交差 / パルス強磁場 |
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| Research Abstract |
This project aims to explore exotic quantum electronic phase in 1 dimensional spin liquids doped with charge carriers. Can Tomonaga-Luttinger liquid be realized ? By introducing external stimulation, can drastic phase change be brought about? With these in mind, we have investigated a cuprate YBa_2Cu_4O_8. YBa_2Cu_4O_8 is unique in that its 1D double chain is remarkably metallic and can be regarded as a doped 1D antiferromagnet. By carefully examining the tranport properties of the metallic double chain, we found novel phenomenon-magnetic field induced dimensional crossover. By applying magnetic field, the interchain transport switches from metallic to insulating around a critical magnetic field B=15 T, indicating electrons are confined within chains. We have proposed a microscopic mechanism behind this switching, based on a real space orbit picture discussed by Lebed and Gorkov. By examining the influence of Zn impurity, then, we have given an experimental verification of the real space orbit picture.
In the last stage of the project, we have attempted to extend the idea of doped spin liquid from 1D magnet to 3D magnet. We focused on 3D spin liquid realized by a geometrical frustration and explored exotic phenomena produced by charge carrier doping. As an output, we have established the existence of a heavy fermion state in LiV_2O_4 spinel and revealed the intimate connection between the the heavy electron mass and the spin liquid state produced by geometrical frustration.
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