Experimental Exploration of the Superconducting Edelstein Effect Utilizing Unidirectional Interfacial Spin Currents

2023 Fiscal Year Final Research Report

• Project/Area Number: 22K18695
• 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: Shizuoka University
• Principal Investigator: Hirobe Daichi 静岡大学, 理学部, 助教 (70823235)
• Project Period (FY): 2022-06-30 – 2024-03-31
• Keywords: キラリティ

Outline of Final Research Achievements

In conductors with broken inversion symmetry, the coupling between electron angular momentum and momentum results in current-induced angular momentum polarization. In this study, we attempted to detect this phenomenon based on the unidirectional interfacial spin currents expected from the broken inversion symmetry. Using magnetoresistance devices, we observed spin-dependent magnetoresistance at the superconducting/ferromagnetic junction interface. A comparison of the experimental results with theoretical predictions revealed the potential involvement of unconventional nonlinear spin transport. Additionally, we investigated the possibility of unconventional nonlinear electrical conduction, demonstrating that orbital magnetic moments can give rise to unique transport phenomena.

Free Research Field

スピントロニクス

Academic Significance and Societal Importance of the Research Achievements

本研究の完遂は、超伝導体を用いた電気－スピン変換に立脚する超伝導スピントロニクスの発展に寄与するものである。また、本実験の検出原理は超伝導Edelstein効果に限定されるものではなく、スピン三重項Cooper対を選択的に検出する方法論の可能性も示唆しており、関連する実験及び理論研究にも波及効果を有する。他方、軌道磁気モーメントが誘発する特異な電気伝導は、相対論的補正としてのスピン軌道結合を必要としない。したがって、軽元素のみを用いて引き出すことが原理的には可能であり、物質群のさらなる拡張が期待される。