Theoretical study on interplays of quantum interference and inter-electron interaction in nanoscale and mesoscale systems

2017 Fiscal Year Final Research Report

• Project/Area Number: 26400319
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Condensed matter physics I
• Research Institution: Osaka City University
• Principal Investigator: Oguri Akira 大阪市立大学, 大学院理学研究科, 教授 (10204166)
• Co-Investigator(Renkei-kenkyūsha): SAKANO RUI 東京大学, 物性研, 助教 (00625022)
• Research Collaborator: TANAKA YOICHI 株式会社先端力学シミュレーション研究所, 主任 ; Hewson A. C. Imperial College London, Department of Mathematics, Senior Research Investigator ; TERATANI YOSHIMICHI 大阪市立大学, 大学院理学研究科, 大学院生 ; NAKATA YUKIHIRO 大阪市立大学, 大学院理学研究科, 大学院生 ; KOIKE NORITAKA 大阪市立大学, 大学院理学研究科, 大学院生 ; MATSUMOTO RYUTA 大阪市立大学, 大学院理学研究科, 大学院生 ; MATSUMOTO MASAYA 大阪市立大学, 大学院理学研究科, 大学院生 ; MATSUMOTO YUTA 大阪市立大学, 大学院理学研究科, 大学院生
• Project Period (FY): 2014-04-01 – 2018-03-31
• Keywords: 物性理論 / 量子ドット / 近藤効果 / フェルミ流体 / 電子相関 / 電流ゆらぎ / 非平衡 / 国際情報研究

Outline of Final Research Achievements

We have microscopically extended the Fermi-liquid theory for quantum dots and magnetic impurities in metals to explore low-energy non-equilibrium transport away from the particle-hole symmetric point. It reveals that the leading finite-temperature and finite-bias-voltage corrections to the transport coefficients are determined by the linear and non-linear-three-body susceptibilities of impurity electrons. Our field-theoretical description gives a clear answer to the long-standing problem, and can be applied to a wide class of Kondo systems and other strongly correlated electron systems.
We have also studied a magnetic-field induced crossover from the SU(4) to SU(2) Kondo state observed in carbon nanotube quantum dots. Our results for the conductance and excitation spectrum, obtained by using the numerical renormalization group approach, agree reasonably with the experiments, which suggests the crossover is caused by a cancellation of the spin and orbital Zeeman splittings.

Free Research Field

物性理論