Theoretical quest for new spin currents produced by superconducting vortex flows

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K05253
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 29010:Applied physical properties-related
• Research Institution: Okayama University
• Principal Investigator: Adachi Hiroto 岡山大学, 異分野基礎科学研究所, 准教授 (10397903)
• Co-Investigator(Kenkyū-buntansha): 大江 純一郎 東邦大学, 理学部, 教授 (40510251)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: スピン流 / スピンホール効果 / 超伝導渦糸

Outline of Final Research Achievements

In this project, we have clarified a new spin-transport principle employing superconducting vortices. In a superconducting vortex state, while the Cooper pair itself does not carry spins, the vortex core can host spin polarization. Therefore, we can think of a spin current carried by the motion of superconducting vortices. We have microscopically calculated spin current operator carried by the superconducting vortices, and found that the spin current operator has a similar form as the heat current operator. Moreover, we have evaluated the vortex spin-Hall conductivity using the Kubo formula, and revealed that the vortex spin-Hall conductivity is proportional to the vortex Nernst conductivity because of the similarity between the spin-current and heat-current operators.

Free Research Field

スピントロニクス、超伝導

Academic Significance and Societal Importance of the Research Achievements

本研究課題では、超伝導の量子渦糸にスピンを閉じ込めて輸送するという、全く新しいスピン輸送の原理を理論的に明らかとした。この成果により、これまでにない有効なスピン情報の輸送手段が付け加えられたといえる。