Topological Transitions in Spin Transport in Nanostructures

2017 Fiscal Year Final Research Report

• Project/Area Number: 26390014
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Nanostructural physics
• Research Institution: Institute of Physical and Chemical Research
• Principal Investigator: Saarikoski Henri 国立研究開発法人理化学研究所, 創発物性科学研究センター, 研究員 (50722245)
• Co-Investigator(Kenkyū-buntansha): 多々良 源 国立研究開発法人理化学研究所, 創発物性科学研究センター, チームリーダー (10271529)
• Co-Investigator(Renkei-kenkyūsha): NITTA Junsaku 東北大学, 大学院工学研究科, 教授 (00393778)
• Research Collaborator: Frustaglia Diego University of Sevilla, Prof.
• Project Period (FY): 2014-04-01 – 2018-03-31
• Keywords: spintronics / geometry / interference / spin-orbit / topology / Rashba

Outline of Final Research Achievements

We studied theoretically various quantum mechanical systems involving spin, i.e., electrons's internal angular momentum. We calculated geometric effects in spin interferometers and showed that the geometric contribution of spin phase can be switched on and off using an external magnetic field. The transition between 'on and 'off' states was found to involve a new quantity called an effective geometric phase that is directly observable in experiments. Together with experimentalists we further showed that domain wall mobility may be greatly enhanced in synthetic antiferromagnets, i.e., double-layer metallic wires that are antiferromagnetically coupled to each other. The effect was found to be due to nonadiabatic driving of anisotropically coupled walls. This mechanism can be used to design efficient domain-wall devices. These results are also interdisciplinary since they are connected with the mathematics of differential geometry.

Free Research Field

spintronics