New approach to the physics of two dimensional electron systems

• Project/Area Number: 21244047
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Condensed matter physics I
• Research Institution: The University of Tokyo
• Principal Investigator: OKAMOTO Tohru 東京大学, 理学(系)研究科(研究院), 准教授 (60245371)
• Co-Investigator(Renkei-kenkyūsha): MASUTOMI Ryuichi 東京大学, 大学院理学系研究科, 助教 (00397027)
• Project Period (FY): 2009-04-01 – 2013-03-31
• Project Status: Completed (Fiscal Year 2013)
• Budget Amount: ¥46,930,000 (Direct Cost: ¥36,100,000、Indirect Cost: ¥10,830,000); Fiscal Year 2012: ¥5,980,000 (Direct Cost: ¥4,600,000、Indirect Cost: ¥1,380,000); Fiscal Year 2011: ¥6,630,000 (Direct Cost: ¥5,100,000、Indirect Cost: ¥1,530,000); Fiscal Year 2010: ¥7,280,000 (Direct Cost: ¥5,600,000、Indirect Cost: ¥1,680,000); Fiscal Year 2009: ¥27,040,000 (Direct Cost: ¥20,800,000、Indirect Cost: ¥6,240,000)
• Keywords: 表面・界面 / 低温物性 / 表面物性 / 表面・界面物性 / 半導体物性 / 強相関電子系

Research Abstract

We study magnetotransport in a high-mobility Si two-dimensional electron system by in situ tilting of the sample relative to the magnetic field. A pronounced dip in the longitudinal resistivity is observed during the Landau-level crossing process for noninteger filling factors. This indicates that electrons in the relevant Landau levels become localized at the coincidence.
Cyclotron resonance of two-dimensional electrons is studied at low temperatures for a high-mobility Si/SiGe which exhibits a metallic temperature dependence of dc resistivity. The relaxation time shows a negative temperature dependence, which is similar to that of the transport scattering time.
Two-dimensional (2D) superconductivity was studied by magnetotransport measurements on single-atomic-layer Pb films on a cleaved GaAs surface. The results are explained in terms of an inhomogeneous superconducting state predicted for 2D metals with a large Rashba spin splitting.

Research Products

• [Journal Article] Two-Dimensional Superconducting State of Monolayer Pb Films Grown on GaAs(110) in a Strong Parallel Magnetic Field (2013)
  • Author(s): T. Sekihara, R. Masutomi, and T. Okamoto
  • Journal Title: Physical Review Letters Volume: 111 Issue: 5 Pages: 5700-5700
  • DOI: 10.1103/physrevlett.111.057005
  • Peer Reviewed
• [Journal Article] Low-Temperature Scanning Tunneling Microscopy and Transport Measurements on Adsorbate-Induced Two-Dimensional Electron Systems (2013)
  • Author(s): R. Masutomi, N. Toriyama, T. Okamoto
  • Journal Title: AIP Conference Proceedings Volume: 1566 Pages: 291-291
  • DOI: 10.1063/1.4848400
  • Peer Reviewed
• [Journal Article] Temperature, electron density and in-plane magnetic field dependence of cyclotron relaxation time in the two-dimensional metallic phase (2013)
  • Author(s): R. Masutomi, T. Chiba, K. Sasaki, I. Yasuda, A. Sekine, K. Sawano, Y. Shiraki, T. Okamoto
  • Journal Title: Journal of Physics: Conference Series Volume: 456 Pages: 12027-12027
  • DOI: 10.1088/1742-6596/456/1/012027
  • Peer Reviewed
• [Journal Article] Magnetic-field-independent superconductivity of ultrathin Pb films on cleaved GaAs surface (2013)
  • Author(s): T. Sekihara, R. Masutomi, and T. Okamoto
  • Journal Title: Journal of Physics: Conference Series Volume: 456 Pages: 12034-12034
  • DOI: 10.1088/1742-6596/456/1/012034
  • Peer Reviewed
• [Journal Article] In-plane magnetic field dependence of cyclotron relaxation time in a Si two-dimensional electron system (2012)
  • Author(s): T. Chiba, R. Masutomi, K. Sawano, Y. Shiraki, and T. Okamoto
  • Journal Title: Physical Review B Volume: 86 Issue: 4 Pages: 45310-45310
  • DOI: 10.1103/physrevb.86.045310
  • Peer Reviewed
• [Journal Article] Magnetotransport in adsorbate-induced two-dimensional electron systems on cleaved InAs surfaces (2011)
  • Author(s): T. Okamoto, T. Mochizuki, M. Minowa, K. Komatsuzaki, and R. Masutomi
  • Journal Title: Journal of Applied Physics Volume: 109 Issue: 10 Pages: 102416-102416
  • DOI: 10.1063/1.3578263
  • Peer Reviewed
• [Journal Article] Metallic Behavior of Cyclotron Relaxation Time in Two-Dimensional Systems (2011)
  • Author(s): R. Masutomi, K. Sasaki, I. Yasuda, A. Sekine, K. Sawano, Y. Shiraki, and T. Okamoto
  • Journal Title: Physical Review Letters Volume: 106 Issue: 19 Pages: 196404-196404
  • DOI: 10.1103/physrevlett.106.196404
  • Peer Reviewed
• [Journal Article] Cyclotron resonance in the two-dimensional metallic phase of Siquantum wells (2011)
  • Author(s): R.Masutomi, K.Sasaki, I.Yasuda, A.Sekine, K.Sawano, Y.Shiraki, T.Okamoto
  • Journal Title: AIP Conference Proceedings Volume: 334 Pages: 012057-012057
  • DOI: 10.1088/1742-6596/334/1/012057
  • Peer Reviewed
• [Journal Article] Cyclotron Resonance of Two Dimensional Electrons near the Metal-Insulator Transition (2011)
  • Author(s): R.Masutomi, K.Sasaki, I.Yasuda, A.Sekine, K.Sawano, Y.Shiraki, T.Okamoto
  • Journal Title: AIP Conference Proceedings Volume: 1399 Pages: 277-278
  • DOI: 10.1063/1.3666361
  • Peer Reviewed
• [Journal Article] Magnetotransport in adsorbate-induced twodimensional electron systems on cleaved InAs surfaces (2011)
  • Author(s): T.Okamoto, T.Mochizuki, M.Minowa, K.Komatsuzaki, R.Masutomi
  • Journal Title: Journal of Applied Physics Volume: (掲載確定)
  • Peer Reviewed
• [Journal Article] Optical Hall Effect in the Integer Quantum Hall Regime (2010)
  • Author(s): Y.Ikebe, T.Morimoto, R.Masutomi, T.Okamoto, H.Aoki, R.Shimano
  • Journal Title: Physical Review Letters Volume: 104
  • Peer Reviewed
• [Journal Article] Cyclotron resonance of two-dimensional electrons in a Si quantum well (2010)
  • Author(s): R.Masutomi, K.Toyama, K.Sasaki, K.Sawano, Y.Shiraki, T.Okamoto
  • Journal Title: Physica E 42 Pages: 1184-1187
  • Peer Reviewed
• [Journal Article] Well-width dependence of valley splitting in Si/SiGe quantum wells (2009)
  • Author(s): K. Sasaki, R. Masutomi, K. Toyama, K. Sawano, Y. Shiraki, and T. Okamoto
  • Journal Title: Applied Physics Letters Volume: 95 Issue: 22 Pages: 222109-222109
  • DOI: 10.1063/1.3270539
  • Peer Reviewed
• [Journal Article] Insulating phases induced by crossing of partially filled Landau levels in a Si quantum well (2009)
  • Author(s): T. Okamoto, K. Sasaki, K. Toyama, R. Masutomi, K. Sawano, and Y. Shiraki
  • Journal Title: Physical Review B Volume: 79 Issue: 24
  • DOI: 10.1103/physrevb.79.241302
  • Peer Reviewed
• [Journal Article] Insulating phases induced by crossing of partially filled Landau levels in a Si quantum well (2009)
  • Author(s): T.Okamoto, K.Sasaki, K.Toyama, R.Masutomi, K.Sawano, Y.Shiraki
  • Journal Title: Physical Review B 79
  • Peer Reviewed
• [Journal Article] Well-width dependence of valley splitting in Si/SiGe quantum wells (2009)
  • Author(s): K.Sasaki, R.Masutomi, K.Toyama, K.Sawano, Y.Shiraki, T.Okamoto
  • Journal Title: Applied Physics Letters 95
  • Peer Reviewed
• [Presentation] Two-dimensonal superconductivity with broken inversion symmetry in one-atomic-layer metal films on cleaved GaAs surfaces (2014)
  • Author(s): T. Sekihara, T. Miyake, H. Ichinomiya, R. Masutomi, and T. Okamoto
  • Organizer: The March Meeting 2014 of the American Physical Society
  • Place of Presentation: Denver, USA
• [Presentation] Two-dimensonal superconductivity with broken inversion symmetry in one-atomic-layer metal films on cleaved GaAs surfaces (2013)
  • Author(s): T. Sekihara, T. Miyake, H. Ichinomiya, R. Masutomi, and T. Okamoto
  • Organizer: The International Conference on Strongly Correlated Electron Systems
  • Place of Presentation: Tokyo, Japan
• [Presentation] STM/STS and transport measurements in adsorbate-induced two-dimensional electron systems (2013)
  • Author(s): R. Masutomi and T. Okamoto
  • Organizer: International Symposium on Advanced Nanodevices and Nanotechnology
  • Place of Presentation: Hawaii, USA
• [Presentation] Strongly correlated two-dimensional system and superconductivity in one atomic layer (2013)
  • Author(s): R. Masutomi
  • Organizer: Yonsei-Todai Symposium
  • Place of Presentation: Tokyo, Japan
• [Presentation] Magnetic-field-independent superconductivity of ultrathin Pb films on cleaved GaAs surface (2012)
  • Author(s): T.Sekihara, R. Masutomi, and T. Okamoto
  • Organizer: 20th International Conference on High Magnetic Fields in Semiconductor Physics
  • Place of Presentation: Chamonix, France
• [Presentation] Low-Temperature Scanning Tunneling Microscopy and Transport Measurements on Adsorbate-Induced Two-Dimensional Electron Systems (2012)
  • Author(s): R. Masutomi, N. Toriyama, T. Okamoto
  • Organizer: 31th International Conference on the Physics of Semiconductors
  • Place of Presentation: Zurich, Switzerland
• [Presentation] Superconductivity of ultrathin metallic films on cleaved GaAs surfaces (2012)
  • Author(s): T. Sekihara, R. Masutomi, and T. Okamoto
  • Organizer: The 10th Japan-Russia Seminar on Semiconductor Surfaces
  • Place of Presentation: Tokyo, Japan
  • Invited
• [Presentation] Temperature, electron density and in-plane magnetic field dependence of cyclotron relaxation time in the two-dimensional metallic phase (2012)
  • Author(s): R. Masutomi, T. Chiba, K. Sasaki, I. Yasuda, A. Sekine, K. Sawano, Y. Shiraki and T. Okamoto
  • Organizer: 20th International Conference on High Magnetic Fields in Semiconductor Physics
  • Place of Presentation: Chamonix, France
• [Presentation] 半導体表面における量子ホール伝導と2次元スピングラス (2011)
  • Author(s): 岡本徹
  • Organizer: 日本物理学会2011年秋季大会
  • Place of Presentation: 富山大学(富山県)(招待講演)
  • Year and Date: 2011-09-21
• [Presentation] 半導体表面における量子ホール伝導と2次元スピングラス (2011)
  • Author(s): 岡本 徹
  • Organizer: 日本物理学会秋季大会
  • Place of Presentation: 富山大学
• [Presentation] Magneto transport in adsorbate-induced twodimensional electron systems on cleaved InAs surfaces (2010)
  • Author(s): T.Okamoto, T.Mochizuki, M.Minowa, K.Komatsuzaki, R.Masutomi
  • Organizer: 30th International Conference on the Physics of Semiconductors
  • Place of Presentation: Seoul, Korea
  • Year and Date: 2010-07-27
• [Presentation] Magnetotransport in adsorbate-induced two-dimensional electron systems on cleaved InAs surfaces (2010)
  • Author(s): T. Okamoto
  • Organizer: The 30th International Conference on the Physics of Semiconductors
  • Place of Presentation: Seoul, Korea
• [Presentation] Cyclotron Resonance of Two Dimensional Electrons near the Metal-Insulator Transition (2010)
  • Author(s): R. Masutomi, K. Sasaki, I. Yasuda, A. Sekine, K. Sawano, Y. Shiraki, T. Okamoto
  • Organizer: The 30th International Conference on the Physics of Semiconductors
  • Place of Presentation: Seoul, Korea
• [Presentation] Hysteresis in magnetoresistance of InAs surface inversion layers covered with submonolayer of Fe films (2009)
  • Author(s): T.Mochizuki, R.Masutomi, T.Okamoto
  • Organizer: 18th International Conference on Electronic Properties of Two-Dimensional Systems
  • Place of Presentation: Kobe, Japan
  • Year and Date: 2009-07-23
• [Book] Electrical Detection of Electron-Spin Resonance in Two-Dimensional Systems, Series : the Topic in Applied Physics, Vol.115
  • Author(s): J. Matsunami and T. Okamoto
  • Publisher: Ed. Marco Fanciulli (著書・分担執筆)
• [Remarks]
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• [Remarks] Recent publications (Okamoto group)
  • URL: http://dolphin.phys.s.u-tokyo.ac.jp/research/list.html
• [Remarks]
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• [Remarks]
  • URL: http://dolphin.phys.s.u-tokyo.ac.jp/
• [Remarks]
  • URL: http://dolphin.phys.s.u-tokyo.ac.jp/