| Project/Area Number |
10640341
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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 | KYOTO UNIVERSITY |
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Principal Investigator |
FURUSAKI Akira (2001) Kyoto University, Yukawa institute for Theoretical Physics, Associate Professor, 基礎物理学研究所, 助教授 (10238678)
SIGRIST Manfred W. (SIGRIST Manfred) (1998-2000) 京都大学, 基礎物理学研究所, 教授 (60293966)
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| Co-Investigator(Kenkyū-buntansha) |
MORINARI Takao Kyoto University, Yukawa Institute for Theoretical Physics, Research Associate, 基礎物理学研究所, 助手 (70314284)
古崎 昭 京都大学, 基礎物理学研究所, 助教授 (10238678)
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| Project Period (FY) |
1998 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2001: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2000: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1999: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1998: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | Unconventional superconductivity / Sr_2RuO_4 / p-wave superconductivity / Ginzburg-Landau theory / Random spin system / Renormalizagion group / One-dimensional Hubbard model / スピン三重項超伝導 / ホール効果 / ギンツブルグランダウ理論 / 拡張ハバード模型 / モット絶縁体 / 高温超伝導 / 強相関電子系 / 磁性 / 時間反転対称性の破れ / スビン軌道相互作用 / カイラル状態 / 分数量子ホール系 / スピン軌道相互作用 / 自発的ホール効果 / 磁束クリープ / 複合フェルミオン / 表面状態 / ジョセフソン効果 |
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| Research Abstract |
1. Theoretical study on the spin-triplet superconducting state in Sr_2RuO_4. A first important step has been the identification of the Cooper pair symmetry. Experiments have concluded that the pairing channel is oddparity, spin-triplet, and breaks time-reversal symmetry. The promising candidate for the superconducting state of Sr_2RuO_4 having these symmetry properties is the so-called chiral p-wave state of p_x + ip_y type, an analog to the A-phase of superfluid ^3He. The microscopic origin for the stability of the chiral p-wave state has been examined from the point of view of "chiral" feedback effects in charge and spin channels, and the crucial role of spin-orbit coupling and the multi-orbital electronic structure has been clarified. A number of phenomena have been examined which are consequences of the chiral p_x + ip_y symmetry. They include (1) the Josephson effect, (2) the quasiparticle spectra at interfaces, around impurities or inside vortices, and (3) the spontaneous Hall effect. Another important issue has been the development of a phenomenology of the so-called 3-Kelvin phase, an inhomogeneous superconducting phase in Sr_2RuO_4 with Ru-metal inclusion.
2. A mechanism of unconventional superconductivity in a two-dimensional double-exchange system with spin-orbit coupling has been proposed.
3. The finite-temperature thermodynamics and the spin correlation at zero temperature in random spin chains with both ferromagnetic and antiferromagnetic exchange couplings have been studied.
4. The ground-state phase diagram of the one-dimensional extended Hubbard model has been reexamined for half filling. We have shown analytically the existence of a bond-ordered state.
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