2020 Fiscal Year Final Research Report
Microscopic theory for multipole ordering and superconductivity in f-electron many-body systems on the basis of a j-j coupling scheme
Project/Area Number |
16H04017
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Research Category |
Grant-in-Aid for Scientific Research (B)
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Allocation Type | Single-year Grants |
Section | 一般 |
Research Field |
Condensed matter physics II
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Research Institution | Tokyo Metropolitan University |
Principal Investigator |
Hotta Takashi 東京都立大学, 理学研究科, 教授 (00262163)
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Co-Investigator(Kenkyū-buntansha) |
服部 一匡 東京都立大学, 理学研究科, 准教授 (30456199)
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Project Period (FY) |
2016-04-01 – 2021-03-31
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Keywords | 2チャンネル近藤効果 / j-j結合描像 / 多極子 / 非フェルミ液体 / 量子臨界点 / 強相関f電子 / 非クラマース二重項 / 超伝導 |
Outline of Final Research Achievements |
In the compounds containing rare-earth or actinide ion with plural numbers of f electrons, it has been well known that there occur some intriguing phenomena such as non-Fermi liquid state, multipole ordering, and unconventional superconductivity. In the present research project, we have developed microscopic theories for magnetism and superconductivity for the system with plural numbers of f electrons based on a j-j coupling scheme. Namely, first we define one-f-electron state characterized by total angular momentum and then, we include Coulomb interactions among such f-electron states. For instance, we remark two-channel Kondo effect which has been well known as a source of non-Fermi liquid state. In addition to the case of Pr ion including two f electrons, we have discovered the two-channel Kondo effect for the case of Nd ion including three f electrons. Moreover, also for the case of Np or Pu ion including four f electrons, we have shown the emergence of two-channel Kondo effect.
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Free Research Field |
物性理論
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Academic Significance and Societal Importance of the Research Achievements |
複数のf電子を持つ希土類及びアクチノイドイオンを含む化合物において,さまざまな興味深い現象が生じることは1980年代から知られていたが,その理解はLS結合描像に基づく現象論的なものにとどまることが多く,微視的な理解はそれほど進んでいなかった。本研究において,j-j結合描像を積極的に活用し,複数のf電子を持つ希土類及びアクチノイドイオンを含む化合物の磁性や超伝導の微視的理論を展開したことの意義は大きい。特に,f電子が2個よりも多い場合にも理論を拡張し,従来知られていなかったNdイオンでの2チャンネル近藤効果を発見したことは重要な成果である。今後,重希土類系へのさらなる理論の展開も期待される。
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