Electron spin control by z-polarization

• Project/Area Number: 16K04977
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Optical engineering, Photon science
• Research Institution: Shizuoka University
• Principal Investigator: Ito Tetsu 静岡大学, 電子工学研究所, 准教授 (70425099)
• Research Collaborator: Muramatsu Hiroki
• Project Period (FY): 2016-10-21 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000); Fiscal Year 2018: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2017: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2016: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
• Keywords: 電子スピン / 正孔スピン / スピン間相互作用 / 結合量子井戸 / スピン重ね合わせ / z偏光 / スピン偏極 / 量子井戸 / 量子エレクトロニクス / スピンエレクトロニクス / 光物性

Outline of Final Research Achievements

Hole spin relaxation in coupled quantum well was investigated by time- and polarization-resolved pump and probe measurements. Two spin relaxation components were observed. Long-relaxation component observed in 15 nm quantum well is considered to be electron spin relaxation which is determined by DP spin relaxation mechanism because it was increased with increasing temperature. On the other hand, Long-relaxation component observed in 10 nm quantum well is hole spin relaxation affected by band mixing in valence band because it monotonically decreased with increasing temperature. The hole spin relaxation time in CQW where electron spin interaction is reduced was prolonged to 200 ps.

Academic Significance and Societal Importance of the Research Achievements

光学的手法で半導体量子構造体における電子状態を制御・観測し，電子スピンを積極的に工学分野へ応用しようとする試みが国内外で活発化している．これまでの研究では半導体量子構造内の電子スピンの挙動やスピン間に働く相互作用を解き明かすためには外部磁場の印加が必要不可欠であった．光パルスによって電子スピンを任意の方向へ生成，制御することで，従来の外部磁場によるスピン操作では達成出来なかった空間制御と高速応答を実現でき，半導体中のスピンを量子ビットとして用いる量子情報素子への応用が期待できる．本研究成果によりえられた正孔のスピン緩和に関する結果は，任意の方向へのスピン生成のために重要な知見である．

Research Products

• [Presentation] Observation of Phase Relaxation in Spin Superposition by Polarization- and Time-Resolved Pump and Probe Measurements (2018)
  • Author(s): Hiroki Muramatsu, Tetsu Ito, Hideki Gotoh, Masao Ichida, Hiroaki Ando
  • Organizer: 2018 International Conference on Solid State Devices and Materials
  • Int'l Joint Research
• [Presentation] 偏光時間分解ポンププローブ測定によるスピン重ね合わせ状態における位相緩和の観測 (2018)
  • Author(s): 村松 弘基，伊藤 哲，後藤 秀樹，市田 正夫，安藤 弘明
  • Organizer: 2018年 第79回 応用物理学会秋季学術講演会
• [Presentation] Phase Relaxation of Hole-Spin Superposition in GaAs/AlGaAs Quantum Wells (2018)
  • Author(s): Tetsu Ito, Hiroki Muramatsu, Hideki Gotoh, Masao Ichida, Hiroaki Ando
  • Organizer: The 4th International Conference on Nano Electronics Research and Education
  • Int'l Joint Research
• [Presentation] Observation of electron- and hole-spin relaxation by pump and probe measurement under different excitation polarization (2017)
  • Author(s): Hiroki Muramatsu, Tetsu Ito, Hideki Gotoh, Masao Ichida, Hiroaki Ando
  • Organizer: The First Materials Research Society of Thailand International Conference
  • Int'l Joint Research
• [Presentation] Control of electron- and hole-spin state by polarized photon (2016)
  • Author(s): Tetsu Ito
  • Organizer: The 18th Takayanagi Kenjiro Memorial Symposium
  • Place of Presentation: 静岡大学（静岡県浜松市）
  • Year and Date: 2016-11-16
  • Int'l Joint Research / Invited