spin-current generation based on static-dynamic chirality conversion in chiral organic crystals

2021 Fiscal Year Final Research Report

• Project/Area Number: 20K20903
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 13:Condensed matter physics 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): 2020-07-30 – 2022-03-31
• Keywords: スピン流 / キラリティ

Outline of Final Research Achievements

Chiral molecules can exhibit spin-selective charge emission, known as chiral-induced spin selectivity. Despite the constituent light elements of the molecules, the spin polarization can approach that of typical ferromagnets. However, the mechanism of the spin selectivity is elusive. A hypothesis on the mechanism has been proposed that time-reversal symmetry breaking is essential. In this study, we tested the working hypothesis by investigating charge-to-spin conversion in a chiral organic crystal. We found a pair of oppositely polarized spins and effective enhancement of spin-orbit interaction, both of which are consistent with the working hypothesis based on time-reversal symmetry breaking. We anticipate that our results will give clues to the mechanism of chirality-induced spin selectivity.

Free Research Field

スピントロニクス

Academic Significance and Societal Importance of the Research Achievements

従来のスピントロニクスでは、電気的スピン流生成のために、第一に強磁性金属のスピン交換結合、第二に貴金属や異種接合界面における強いスピン軌道相互作用が活用された。これらの物質観では、非磁性かつスピン軌道相互作用の小さな軽元素は、一見するとスピン流生成に不適である。それゆえ、キラルな有機結晶での静的-動的キラリティ変換に関する本研究成果は、従来の概念体系にないスピントロニクス効果の存在を支持するものである。また、π電子系を基軸とする本アプローチは、固体物性と分子科学を架橋する点で有為であり、双方のスピントロニクス関連分野に新たな物質設計指針を提供することも期待できる。