1992 Fiscal Year Final Research Report Summary
Magnetism and Superconductivity in Highly Correlated Systems
| Project/Area Number |
03044037
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Joint Research |
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| Research Institution | The University of Tokyo |
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Principal Investigator |
FUKUYAMA Hidetoshi Professor, Faculty of Science, Tokyo Univ., 理学部, 教授 (10004441)
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| Co-Investigator(Kenkyū-buntansha) |
H.R.OTT Prof., ETH, PSI, ポールシェラー研究所, 教授
T.M.RICE Prof., ETH, 教授
三宅 和正 大阪大学, 基礎工学部, 助教授 (90109265)
NAGAOSA N Assoc. Prof., Faculty of Engineering, Tokyo Univ., 工学部, 助教授 (60164406)
KURAMOTO Y Prof., Faculty of Science, Tohoku Univ., 理学部, 教授 (70111250)
KAWAKAMI N Assoc. Prof., RIFP, Kyoto Univ., 基礎物理学研究所, 助教授 (10169683)
今田 正俊 東京大学, 物性研究所, 助教授 (70143542)
上田 和夫 スイス連邦工科大学, ポールシェラー研究所, 客員教授 (70114395)
MIYAKE K Assoc. Prof., Faculty of Engineering, Science, Osaka Univ.
UEDA K Visiting Professor, Paul Scherer Institute
IMADA M Assoc. Prof., ISSP, Tokyo Univ.
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| Project Period (FY) |
1991 – 1992
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| Keywords | High Tc / Oxides / Heavy electrons / Organic conductors / Quantum wires / t-J model / Hubbard model / Mott transition |
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| Research Abstract |
The aims of this project are to explore the electronic states and resulting properties of strongly correlated systems, which include high Tc cuprates. oxides in general, heavy electrons, organic conductors and quantum wires.
1.High Tc Cuprates
The magnetic excitations and transport properties are successfully investigated based on the t-J model (Fukuyama, Nagaosa). A new proposal has been based on the origin of the mysterious insulating state of PrBa_2Cu_3O_7(Rice).
2.Oxides. Mott transition
Detailed numerical calculations have been carried on the two-dimensional Hubbard model, which elucidate that the effective mass diverges as the Mott transition is approached (Imada). Since this is not seen in cuprates, this finding casts doubt on the validity of the Hubbard model to high Tc oxides and hence two different types of Mott transition have been proposed (Imada).
3.Heavy Electrons
The phase diagram of one-dimensional dense Kondo system has been explored by both analytical and numerical method (Ueda). The possibility of the de Haas van Alphen oscillation in the anisotropic superconducting state has been pointed out (Miyake).
4.Discovery of Exact Solutions
Exact solutions of the extended range t-J model have been found (Kuramoto) and explored (Kuramoto, Kawakami).
5.Organic Conductors
Unusual properties of (DCNQI)2Cu have been explained based on the Peierls transition with strong correlations (Fukuyama).
6.Quantum Wires
In quantum wires made of semiconductors, electrons form one-dimensional band and hence the Tomonaga-Luttinger liquid. The tunneling characteristics and transport properties have been investigated. (Nagaosa, Fukuyama).
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