Emergent electromagnetism in magnets

2016 Fiscal Year Final Research Report

• Project/Area Number: 24224009
• Research Category: Grant-in-Aid for Scientific Research (S)
• Allocation Type: Single-year Grants
• Research Field: Condensed matter physics II
• Research Institution: The University of Tokyo
• Principal Investigator: Nagaosa Naoto 東京大学, 大学院工学系研究科(工学部), 教授 (60164406)
• Co-Investigator(Kenkyū-buntansha): BAHRAMY MOHAMMAD 東京大学, 工学(系)研究科(研究院), 講師 (10587463) ; 十倉 好紀 東京大学, 工学(系)研究科(研究院), 教授 (30143382) ; 佐藤 卓 東北大学, 多元物質科学研究所, 教授 (70354214) ; 岡 隆史 東京大学, 工学(系)研究科(研究院), 講師 (50421847)
• Project Period (FY): 2012-05-31 – 2017-03-31
• Keywords: ベリー位相 / 創発的電磁気現象 / スキルミオン / モノポール / トポロジカル絶縁体

Outline of Final Research Achievements

Emergent electromagnetism, which originates from the quantum mechanical Berry phase, has been developed in both real-space and momentum-space of magnets. In real-space, a swirling spin texture called skyrmion has been studied extensively. Its dynamics corresponding to creation, annihilation, motion, and read-out has been revealed, leading to the foundation of its application to electronics.
In momentum-space, we succeeded to realize the quantized anomalous Hall effect and related various novel phenomena such as dissipationless current in domain wall, skyrmion formation, and axionic insulator. Also the physics of monopole in momentum-space has been explored. New dynamical effects associated with the emergent electromagnetic fields such as nonreciprocal nonlinear responses and photo-induced topological current have been revealed.

Free Research Field

物性理論