Interconversion between charge and spin currents in chiral compounds

2019 Fiscal Year Final Research Report

• Project/Area Number: 19K21039
• Project/Area Number (Other): 18H05854 (2018)
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund (2019); Single-year Grants (2018)
• Review Section: 0202:Condensed matter physics, plasma science, nuclear engineering, earth resources engineering, energy engineering, and related fields
• Research Institution: Institute for Molecular Science
• Principal Investigator: Hirobe Daichi 分子科学研究所, 協奏分子システム研究センター, 助教 (70823235)
• Project Period (FY): 2018-08-24 – 2020-03-31
• Keywords: キラリティ / 磁性 / スピントロニクス / 分子性材料

Outline of Final Research Achievements

I investigated conversion between charge and spin currents in a molecular material and an inorganic metal that exhibit chirality and electric conduction. For the chiral molecular material, I succeeded in detecting giant magnetoresistance that was caused by a highly spin-polarized current. This finding might serve as a guiding principle for developing functional spintronic materials composed of nonmagnetic and light elements. With joint research into the inorganic metal, we also found chirality-related conversion between charge and spin currents. This result shows that there is a spin-current phenomenon unique to chirality even in crystalline systems, although the mechanism would differ from that of chirality-induced spin polarization in molecular systems.

Free Research Field

スピントロニクス

Academic Significance and Societal Importance of the Research Achievements

スピントロニクスは電子の電荷とスピンの両方を制御することで次世代基幹技術の創製を目指す学際領域である。最重要概念は電子スピン角運動量の流れ、スピン流であり、スピン流の学理構築は重要である。電流とスピン流の相互変換として、第一に強磁性金属における強いスピン交換結合、第二に貴金属中の強いスピン軌道相互作用が開拓され、この学理体系は完成されたと思われていた。しかしながら、非磁性かつスピン軌道相互作用の小さな軽元素を用いても電流－スピン流変換できることが最近あきらかになってきた。キラル分子性材料をもちいた本研究はこの潮流に即したものであり、電流－スピン流変換の高効率化の指針を与えるものである。