Coupling between single spin and mechanical oscillation through lattice strain

• Project Area: Science of hybrid quantum systems
• Project/Area Number: 16H01048
• Research Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
• Allocation Type: Single-year Grants
• Review Section: Science and Engineering
• Research Institution: University of Tsukuba
• Principal Investigator: 黒田 眞司 筑波大学, 数理物質系, 教授 (40221949)
• Project Period (FY): 2016-04-01 – 2018-03-31
• Project Status: Completed (Fiscal Year 2017)
• Budget Amount: ¥11,180,000 (Direct Cost: ¥8,600,000、Indirect Cost: ¥2,580,000); Fiscal Year 2017: ¥5,200,000 (Direct Cost: ¥4,000,000、Indirect Cost: ¥1,200,000); Fiscal Year 2016: ¥5,980,000 (Direct Cost: ¥4,600,000、Indirect Cost: ¥1,380,000)
• Keywords: 単一スピン / スピン緩和 / 交換相互作用 / 量子ドット / 格子歪 / 顕微分光 / スピン‐歪結合 / ナノワイヤ / 微小共振器

Outline of Annual Research Achievements

本研究は、遷移元素の原子1個を含む量子ドットを含む微細構造で、遷移元素の単一磁性スピンと格子歪とのカップリングを利用して、単一スピンと機械的振動との結合を実現することを目標として研究を行う。具体的には、遷移元素Crの原子1個を含むCdTe量子ドットを対象として、ドット中の励起子発光より単一Crスピンの振舞い、特に格子歪の影響を調べ、格子歪によるCrスピンを変調および制御する手法の開発を目指す。今年度は、分子線エピタキシー(MBE)法により作製したCr原子1個を含むCdTe自己形成ドットに対し時間分解発光測定を含む種々の光学測定を行い、ドット中の単一Crスピンの振舞いをそのダイナミクスを含めて詳しく調べた。その結果、以下のことを明らかにすることができた。
(1) 2波長のポンププローブフォトルミネッセンス(PL)測定を行い、Crスピンの特定の準位を励起し、別の準位の発光の時間変化を観測することで、Crスピンの緩和過程を調べた。その結果、励起子が存在する明状態ではCrスピンの緩和時間は50 ns程度であるのに対し、励起子が存在しない暗状態では緩和時間は約2 microsと長くなることを見出した。さらに明状態におけるCrスピン緩和のメカニズムはCrと正孔間のスピンフリップ過程によると考察し、実際の緩和過程を再現するモデルを構築した。
(2) 特定のCrスピン準位に対する共鳴励起で、励起光強度を増加させたところ単一の発光線が2つに分裂することを見出した。これは光シュタルク効果によるCrスピン準位の分裂によるもので、光電場との共鳴でCr準位が光の衣を纏った状態(optically dressed)となって準位の分裂が生じたと考えられる。これより光励起によるCrスピン状態の制御が可能であることを示した。

Research Progress Status

29年度が最終年度であるため、記入しない。

Strategy for Future Research Activity

29年度が最終年度であるため、記入しない。

Research Products

• [Int'l Joint Research] CNRS, Institut Neel(France)
• [Int'l Joint Research] CNRS, Institut Neel(France)
• [Journal Article] Dynamics of a Cr spin in a semiconductor quantum dot: Hole-Cr flip-flops and spin-phonon coupling (2018)
  • Author(s): A. Lafuente-Sampietro, H. Utsumi, M. Sunaga, K. Makita, H. Boukari, S. Kuroda, and L. Besombes
  • Journal Title: Physical Review B Volume: 97 Issue: 15 Pages: 155301-155301
  • DOI: 10.1103/physrevb.97.155301
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Structural and magnetic properties of (Zn,Fe)Te thin films grown by MBE under Zn-rich flux condition (2017)
  • Author(s): Takuma Nakamura, Yu Sugimura, Takeru Domon, Satoshi Ishitsuka, Ken Kanazawa, Hironori Ofuchi, Shinji Kuroda
  • Journal Title: Journal of Crystal Growth Volume: 印刷中 Pages: 123-126
  • DOI: 10.1016/j.jcrysgro.2016.12.030
  • Peer Reviewed
• [Journal Article] Atomic Scale Structural Characterization of Epitaxial (Cd,Cr)Te Magnetic Semiconductor (2017)
  • Author(s): Bastien Bonef, Herve Boukari, Adeline Grenier, Isabelle Mouton, Pierre-Henri Jouneau, Hidekazu Kinjo, Shinji Kuroda
  • Journal Title: Microscopy and Microanalysis Volume: 23 Issue: 4 Pages: 717-723
  • DOI: 10.1017/s1431927617000642
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Observation of the inverse spin Hall effect in the topological crystalline insulator SnTe using spin pumping (2017)
  • Author(s): Shinobu Ohya, Akiyori Yamamoto, Tomonari Yamaguchi, Ryo Ishikawa, Ryota Akiyama, Le Duc Anh, Shobhit Goel, Yuki K. Wakabayashi, Shinji Kuroda, Masaaki Tanaka
  • Journal Title: Physical Review B Volume: 96 Issue: 9 Pages: 094424-094424
  • DOI: 10.1103/physrevb.96.094424
  • NAID: 120007134820
  • Peer Reviewed
• [Journal Article] Resonant optical control of the spin of a single Cr atom in a quantum dot (2017)
  • Author(s): A. Lafuente-Sampietro, H. Utsumi, H. Boukari, S. Kuroda, L. Besombes
  • Journal Title: Physical Review B Volume: 95 Issue: 3 Pages: 035303-035303
  • DOI: 10.1103/physrevb.95.035303
  • NAID: 120007135106
  • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] Individual Cr atom in a semiconductor quantum dot: Optical addressability and spin-strain coupling (2016)
  • Author(s): A. Lafuente-Sampietro, H. Utsumi, H. Boukari, S. Kuroda, L. Besombes
  • Journal Title: Physical Review B (Rapid Communications) Volume: 93 Issue: 16
  • DOI: 10.1103/physrevb.93.161301
  • NAID: 120007135516
  • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] Spin dynamics of an individual Cr atom in a semiconductor quantum dot under optical excitation (2016)
  • Author(s): A. Lafuente-Sampietro, H. Utsumi, H. Boukari, S. Kuroda, L. Besombes
  • Journal Title: Applied Physics Letters Volume: 109 Issue: 5 Pages: 053103-053103
  • DOI: 10.1063/1.4959243
  • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
• [Presentation] Optical probe of single Cr spin in a self-assembled CdTe dot (2017)
  • Author(s): A. Lauente-Sampietro, H. Utsumi, M. Sunaga, L. Besombes, H. Boukari, S. Kuroda
  • Organizer: International Symposium on Hybrid Quantum Systems 2017 (HQS2017)
  • Int'l Joint Research
• [Presentation] Resonant optical control of the spin of an individual Cr atom in a quantum dot (2017)
  • Author(s): A. Lafuente-Sampietro, H. Boukari, L. Besombes, H. Utsumi, S. Kuroda
  • Organizer: International Conference on Optics of Excitons in Confined Systems
  • Int'l Joint Research
• [Presentation] Cr原子1個を含むCdTe量子ドットの作製と単一Crスピンの光学的制御 (2016)
  • Author(s): 内海駿人,須永雅弘,Alban Lafuente-Sampietro, Lucien Besombes, Herve; Boukari, 黒田眞司
  • Organizer: 第21回半導体におけるスピン工学の基礎と応用
  • Place of Presentation: 北海道大学(北海道札幌市)
  • Year and Date: 2016-12-12
• [Presentation] Fabrication of CdTe dots containing a single Cr with and without strain (2016)
  • Author(s): H. Utsumi, K. Sakamoto, S. Kuroda, A. Lafuente-Sampietro, H. Boukari, L. Besombes
  • Organizer: 9th International Conference on Physics and Applications of Spin-Related Phenomena in Solids (PASPS-9)
  • Place of Presentation: 神戸国際会議場(兵庫県神戸市)
  • Year and Date: 2016-08-08
  • Int'l Joint Research
• [Presentation] Optical probing and dynamics of a Cr spin in a semiconductor quantum dot (2016)
  • Author(s): A. Lafuente-Sampietro, H. Utsumi, H. Boukari, S. Kuroda, L. Besombes
  • Organizer: 9th International Conference on Physics and Applications of Spin-Related Phenomena in Solids (PASPS-9)
  • Place of Presentation: 神戸国際会議場(兵庫県神戸市)
  • Year and Date: 2016-08-08
  • Int'l Joint Research
• [Presentation] Individual Cr atom in a semiconductor quantum dot -optical addressability and spin-strain coupling (2016)
  • Author(s): A. Lafuente-Sampietro, H. Boukari, L. Besombes, H. Utsumi, S. Kuroda
  • Organizer: 33rd International Conference on the Physics of Semiconductors (ICPS2016)
  • Place of Presentation: Bejing, China
  • Year and Date: 2016-07-31
  • Int'l Joint Research
• [Presentation] Magnetic properties of an individual Cr atom in a semiconductor quantum dot (2016)
  • Author(s): A. Lafuente-Sampietro, H. Boukari, L. Besombes, H. Utsumi, S. Kuroda
  • Organizer: 9th International Conference on Quantum Dots (QD2016)
  • Place of Presentation: Jeju, Korea
  • Year and Date: 2016-05-22
  • Int'l Joint Research