| Project/Area Number |
26400353
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Condensed matter physics II
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| Research Institution | Niigata University |
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Principal Investigator |
ONO Yoshiaki 新潟大学, 自然科学系, 教授 (40221832)
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| Co-Investigator(Renkei-kenkyūsha) |
SANO Kazuhiro 三重大学, 工学部, 教授 (40201537)
YANAGI Yuki 明治大学, 理工学部, 研究員 (70634343)
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| Project Period (FY) |
2014-04-01 – 2017-03-31
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| Project Status |
Completed (Fiscal Year 2016)
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| Budget Amount *help |
¥4,810,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥1,110,000)
Fiscal Year 2016: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2015: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2014: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
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| Keywords | 多バンド系超伝導体 / 電子相関 / 電子格子結合 / A15型超伝導体 / Ta2NiSe5 / 軌道揺らぎ / 励起子揺らぎ / 励起子相 / FFLO状態 / 超伝導 / 多バンドハバード模型 / 乱雑位相近似 / エリアシュベルグ方程式 / 超伝導発現機構 / 励起子秩序 / 構造相転移 / 第一原理計算 / 3鎖ハバード模型 / 36バンドd-p模型 |
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| Outline of Final Research Achievements |
The superconductivity in multi-band electron systems is investigated by using the theoretical approach recently developed for iron-based superconductors. On the basis of the 36-band d-p model for A15-type superconductors derived from the first-principles calculations, the effect of the intersite d-p Coulomb interaction is found to results in the orbital orders responsible for the structural transitions called the martensite transformation for both cases of V3Si and Nb3Sn, and also results in the orbital-fluctuation-mediated superconductivity with a relatively High-Tc. Transition metal chalcogenide Ta2NiSe5, a promising material for the excitonic insulator, is investigated on the basis of the quasi-one-dimensional three-chain Hubbard model and is found to show remarkable Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) excitonic orders whose fluctuation mediate FFLO superconductivity as expected to be observed in semimetallic Ta2NiSe5 under high pressure.
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