Superconductivity and quantum transport phenomena in Jahn-Teller crystals
| Project/Area Number |
24540379
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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 | Tokyo Metropolitan University |
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Principal Investigator |
HOTTA Takashi 首都大学東京, 理工学研究科, 教授 (00262163)
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| Project Period (FY) |
2012-04-01 – 2015-03-31
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| Project Status |
Completed (Fiscal Year 2014)
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| Budget Amount *help |
¥5,200,000 (Direct Cost: ¥4,000,000、Indirect Cost: ¥1,200,000)
Fiscal Year 2014: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2013: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2012: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000)
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| Keywords | ヤーンテラーフォノン / 近藤効果 / ラットリング / バイブロニック状態 / 磁性 / 軌道自由度 / 超伝導 / フェルミ面 |
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| Outline of Final Research Achievements |
We have analyzed the superconducting transition temperature Tc in the two-dimensional orbital-degenerate electron systems coupled with Jahn-Teller oscillations. We have found that Tc is increased for the case of disconnected Fermi-surface structure, since Cooper-pair hopping between different Fermi surfaces is enhanced by the Jahn-Teller oscillation.
We have analyzed the Anderson model coupled with anharmonic Jahn-Teller oscillations by using a numerical renormalization group technique. We have found that the Kondo phenomenon occurs due to the screening of rotational phonon mode with clockwise and anti-clockwise directions by orbital momenta of conduction electrons.
We have discovered chaos in the energy spectrum of anharmonic Jahn-Teller oscillation. We have pointed out that chaos appears as an anomalous peak in the temperature dependence of specific heat. We have proposed that such a peak can be detected in the experiments on cage-structure materials.
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Report
(4 results)
Research Products
(41 results)
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[Presentation] Ryosuke Yamamura and Takashi Hotta2015
Author(s)
Valence Imbalance of Manganese Ions between Surface and Bulk due to Quantum Interference of Friedel Oscillations in Layered Manganites
Organizer
TMU International Symposium on "The Global Human Resource Program Bridging across Physics and Chemistry"
Place of Presentation
首都大学東京南大沢キャンパス、東京
Year and Date
2015-01-30
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