Spin Torque Effect in Mesoscopic Systems

2011 Fiscal Year Final Research Report

• Project/Area Number: 21540320
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Condensed matter physics I
• Research Institution: Osaka University
• Principal Investigator: HATTORI Kiminori 大阪大学, 基礎工学研究科, 准教授 (80228486)
• Project Period (FY): 2009 – 2011
• Keywords: スピントルク / メゾスコピック系 / スピントロニクス / スピンポンピング / 量子スピンホール効果

Research Abstract

Spintronics is a burgeoning field in condensed matter physics which aims to harness electron spin in addition to charge in solid-sate systems. Many ideas for achieving this goal have been proposed to date. Among these, spin torque effect and spin Hall effect in mesoscopic systems are extensively investigated in this study. We obtain the following important results. The spin torque effect occurring in Rashba spin-orbit(SO) coupled systems efficiently produces a pure spin current which is orders of magnitude larger than ordinary spin Hall currents. Reflecting time evolution of spin state, a Rabi oscillation is exhibited in transient spin current pumped from a ESR-driven quantum dot. Helical edge states are formed in a harmonic quantum wire due to the SO interaction induced by lateral confinement, yielding the quantum spin Hall(QSH) effect. Quantized charge transport in the QSH system is destroyed by any weak magnetic disorder, whereas quantized and conserved spin transport survives magnetic disorder as long as bulk insulating gap remains intact.

Research Products

• [Journal Article] Quantized Spin Transport in Magnetically-Disordered Quantum Spin Hall Systems (2011)
  • Author(s): Kiminori Hattori
  • Journal Title: Journal of the Physical Society of Japan, Virtual Journal of Nanoscale Science & Technology, American Institute of Physics and American Physical Society Volume: Vol.80, No.12, Vol.25, Issue 1 Pages: 124712-1-5
  • URL: http://www.vjnano.org/
  • Peer Reviewed
• [Journal Article] Quantum Spin-Hall Effect in a Quantum Wire (2010)
  • Author(s): Kiminori Hattori
  • Journal Title: Journal of the Physical Society of Japan, Virtual Journal of Nanoscale Science & Technology, American Institute of Physics and American Physical Society, The top 20 most downloaded articles in J. Phys. Soc. Jpn Volume: Vol.79, No.10, Vol.22, Issue 18 Pages: 104709-1-5
  • URL: http://www.vjnano.org/
  • Peer Reviewed
• [Journal Article] Spin Current Generated from a Quantum Dot Driven by Pulsed Magnetic Resonance : Real-Time Spin Dynamics (2010)
  • Author(s): Kiminori Hattori
  • Journal Title: Journal of the Physical Society of Japan, Virtual Journal of Nanoscale Science & Technology, American Institute of Physics and American Physical Society Volume: Vol.79, No.6, Vol.22, Issue 2 Pages: 064706-1-6
  • URL: http://www.vjnano.org/
  • Peer Reviewed
• [Journal Article] Spin-Current-Driven Spin Pumping in Rashba Spin-Orbit Coupled Systems : A Spin Torque Effect (2009)
  • Author(s): Kiminori Hattori
  • Journal Title: Journal of the Physical Society of Japan Volume: Vol.78, No.8 Pages: 084703-1-7
  • Peer Reviewed
• [Presentation] 磁気的乱れを有する量子スピンホール系におけるスピン輸送 (2011)
  • Author(s): 服部公則
  • Organizer: 日本物理学会2011年秋季大会,領域4 :トポロジカル絶縁体
  • Place of Presentation: 富山大学五福キャンパス
  • Year and Date: 2011-09-24
• [Presentation] 量子細線の量子スピンホール効果 (2011)
  • Author(s): 服部公則
  • Organizer: 日本物理学会第66回年次大会,領域4 :トポロジカル絶縁体
  • Place of Presentation: 新潟大学五十嵐キャンパス
  • Year and Date: 2011-03-26
• [Presentation] パルスESRで駆動された量子ドットからのスピンポンピング:実時間ダイナミクス (2010)
  • Author(s): 服部公則
  • Organizer: 日本物理学会2010年秋季大会,領域4 :量子ドット
  • Place of Presentation: 大阪府立大学中百舌鳥キャンパス
  • Year and Date: 2010-09-24
• [Presentation] ラシュバスピン軌道結合系におけるスピンカレント駆動スピンポンピング (2009)
  • Author(s): 服部公則
  • Organizer: 日本物理学会2009年秋季大会,領域4 :半導体スピン物性
  • Place of Presentation: 熊本大学黒髪キャンパス
  • Year and Date: 2009-09-27