2013 Fiscal Year Final Research Report
Theoretical study on quantum transport through strongly correlated electrons in quantum dots and nano materials
| Project/Area Number |
23540375
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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 I
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| Research Institution | Osaka City University |
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Principal Investigator |
OGURI Akira 大阪市立大学, 理学(系)研究科(研究院), 教授 (10204166)
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| Co-Investigator(Kenkyū-buntansha) |
SAKANO Rui 東京大学, 物性研, 助教 (00625022)
TANAKA Yoichi アドバンスソフト株式会社, 研究員
HEWSON A. C. Imperial College, Department of Mathematics, Senior Research Investigator
SHIMAMOTO Masashi 大阪市立大学, 大学院・理学研究科, 大学院生
AWANE Miyuki 大阪市立大学, 大学院・理学研究科, 大学院生
SATO Izumi 大阪市立大学, 大学院・理学研究科, 大学院生
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| Project Period (FY) |
2011 – 2013
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| Keywords | 近藤効果 / 強相関電子系 / 量子ドット / 非平衡電流 / ショットノイズ / 超伝導 / アンドレーエフ散乱 / 数値くりこみ群 |
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| Research Abstract |
We have studied effects of inter-electron interaction on transport through quantum dots and nanoscale materials. We have proposed a novel large N expansion, where N is an orbital degeneracy. This method is different from the conventional ones and enables us a systematic calculation beyond the RPA. We have also obtained exact interacting Green's function for the Anderson impurity out of equilibrium at high bias voltages. Furthermore, we have provided an exact expression for nonequilibrium current fluctuations through a quantum dot, which includes a ferromagnetic Hund's rule coupling, in the low-energy Fermi liquid regime. Our result shows that the shot noise can be expressed in terms of renormalized parameters of quasiparticles defined with respect to equilibrium ground state in the particle-hole symmetric case. We have also studied interplay between Kondo and Andreev-Josephson effects of a quantum dot coupled to three terminals, consisting of normal and superconducting leads.
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