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Theoretical studies of topological and electron correlation effects in graphene

Research Project

Project/Area Number 22740196
Research Category

Grant-in-Aid for Young Scientists (B)

Allocation TypeSingle-year Grants
Research Field Condensed matter physics I
Research InstitutionThe University of Tokyo

Principal Investigator

EZAWA Motohiko  東京大学, 大学院工学系研究科, 助教 (10504805)

Project Period (FY) 2010-04-01 – 2014-03-31
Project Status Completed (Fiscal Year 2013)
Budget Amount *help
¥3,120,000 (Direct Cost: ¥2,400,000、Indirect Cost: ¥720,000)
Fiscal Year 2012: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2011: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2010: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Keywordsグラフェン / シリセン / トポロジカル絶縁体 / スキルミオン / 量子スピンホール効果 / チャーン数 / メロン / 量子異常ホール効果 / トポロジー / 電子相関 / グラフェン・ナノリボン / 場の理論 / トポロジカル相転移 / スカーミオン / バイメロン / ナノグラフェン / グラフェン・ナノディスク / ディラック電子 / 量子ドット / スピン軌道相互作用 / 渦度
Research Abstract

I studied electronic and topological properties of graphene and silicene (graphene's cousin).In particular, I analyzed various topological insulators and their topological phase transitions. Main results read as follows: The zero-energy sector of the triangular zigzag graphene is investigated based on the Dirac theory of graphene.Analytic wave functions of triangular graphene are obtained. A vortex with the winding number 2 emerges in triangular graphene. Graphene nanodisk arrays have multi-degenerate perfect flat bands and are ferromagnet. The band gap of silicene can be controlled by external electric field applied perpendicular to silicene. Silicene shows the quantum anomalous-Hall effect when ferromagnet is attached. Furthermore, silicene undergoes a topological phase transition by photo-irradiation, where single-Dirac cone states appear at the critical point.I also studied the skyrmion, which is a topological structure in magnet.

Report

(4 results)
  • 2013 Final Research Report ( PDF )
  • 2012 Annual Research Report
  • 2011 Annual Research Report
  • 2010 Annual Research Report
  • Research Products

    (49 results)

All 2013 2012 2011 2010 Other

All Journal Article (19 results) (of which Peer Reviewed: 18 results) Presentation (26 results) (of which Invited: 4 results) Book (2 results) Remarks (2 results)

  • [Journal Article] Photo-Induced Topological Phase Transition and Single Dirac-Cone State in Silicene2013

    • Author(s)
      M. Ezawa
    • Journal Title

      Phys. Rev. Lett

      Volume: 110 Issue: 2 Pages: 26603-26603

    • DOI

      10.1103/physrevlett.110.026603

    • Related Report
      2013 Final Research Report 2012 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Spin-Valley Optical Selection Rule and Strong Circular Dichroism in Silicene2012

    • Author(s)
      M. Ezawa
    • Journal Title

      Phys. Rev

      Volume: B86 Issue: 16 Pages: 161407-161407

    • DOI

      10.1103/physrevb.86.161407

    • Related Report
      2013 Final Research Report 2012 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Topological Phase Transition and Electrically Tunable Diamagnetism in Silicene2012

    • Author(s)
      M. Ezawa
    • Journal Title

      Eur. Phys. J

      Volume: B85 Issue: 11 Pages: 363-363

    • DOI

      10.1140/epjb/e2012-30577-0

    • Related Report
      2013 Final Research Report 2012 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Quasi-Topological Insulator and Trigonal Warping in Gated Bilayer Silicene2012

    • Author(s)
      M. Ezawa
    • Journal Title

      J. Phys. Soc. Jpn

      Volume: 81 Issue: 10 Pages: 104713-104713

    • DOI

      10.1143/jpsj.81.104713

    • NAID

      40019447567

    • Related Report
      2013 Final Research Report 2012 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Dirac Theory and Topological Phases of Silicon Nanotube2012

    • Author(s)
      M. Ezawa
    • Journal Title

      Europhysics Letters

      Volume: 98 Issue: 6 Pages: 67001-67001

    • DOI

      10.1209/0295-5075/98/67001

    • Related Report
      2013 Final Research Report 2012 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Quantum Hall Effects in Silicene2012

    • Author(s)
      M. Ezawa
    • Journal Title

      J. Phys. Soc. Jpn

      Volume: 81 Issue: 6 Pages: 64705-64705

    • DOI

      10.1143/jpsj.81.064705

    • NAID

      40019309233

    • Related Report
      2013 Final Research Report 2012 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Valley-Polarized Metals and Quantum Anomalous Hall Effect in Silicene2012

    • Author(s)
      M. Ezawa
    • Journal Title

      Phys. Rev. Lett

      Volume: 109 Issue: 5 Pages: 55502-55502

    • DOI

      10.1103/physrevlett.109.055502

    • Related Report
      2013 Final Research Report 2012 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Topological Insulator and Helical Zero Mode in Silicene under Inhomogeneous Electric Field2012

    • Author(s)
      M. Ezawa
    • Journal Title

      New J. Phys

      Volume: 14 Issue: 3 Pages: 33003-33003

    • DOI

      10.1088/1367-2630/14/3/033003

    • Related Report
      2013 Final Research Report 2012 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Complex Structure of Triangular Graphene : Electronic, Magnetic and Electromechanical Properties2012

    • Author(s)
      M. Ezawa
    • Journal Title

      Journal of Nanoscience and Nanotechnology

      Volume: 12 Issue: 1 Pages: 386-386

    • DOI

      10.1166/jnn.2012.5350

    • Related Report
      2013 Final Research Report 2011 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Skyrmion Burst and Multiple Quantum Walk in Thin Ferromagnetic Films2011

    • Author(s)
      M. Ezawa
    • Journal Title

      Phys. Lett

      Volume: A375 Issue: 41 Pages: 3610-3610

    • DOI

      10.1016/j.physleta.2011.08.030

    • Related Report
      2013 Final Research Report
    • Peer Reviewed
  • [Journal Article] Compact Merons and Skyrmions in Thin Chiral Magnetic Films2011

    • Author(s)
      M. Ezawa
    • Journal Title

      Phys. Rev

      Volume: B83 Issue: 10 Pages: 100408-100408

    • DOI

      10.1103/physrevb.83.100408

    • Related Report
      2013 Final Research Report 2011 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Giant Skyrmions Stabilized by Dipole-Dipole Interactions in Thin Ferromagnetic Films2010

    • Author(s)
      M. Ezawa
    • Journal Title

      Phys. Rev. Lett

      Volume: 105 Issue: 19 Pages: 197202-197202

    • DOI

      10.1103/physrevlett.105.197202

    • Related Report
      2013 Final Research Report
    • Peer Reviewed
  • [Journal Article] Manipulation of Two Spin Qubits in a Double Quantum Dot using an Electric Field2010

    • Author(s)
      A. Shitade, M. Ezawa, N. Nagaosa
    • Journal Title

      Phys. Rev

      Volume: B82 Issue: 19 Pages: 195305-195305

    • DOI

      10.1103/physrevb.82.195305

    • Related Report
      2013 Final Research Report
  • [Journal Article] Current Modulator based on Topological Insulator with Sliding Magnetic Superlattice2010

    • Author(s)
      M. Ezawa and J. Zang
    • Journal Title

      Phys. Rev

      Volume: B81 Issue: 19 Pages: 193302-193302

    • DOI

      10.1103/physrevb.81.193302

    • Related Report
      2013 Final Research Report
    • Peer Reviewed
  • [Journal Article] Dirac fermions in a graphene nanodisk and a graphene corner : Texture of vortices with an unusual winding number2010

    • Author(s)
      M. Ezawa
    • Journal Title

      Phys. Rev

      Volume: B81 Issue: 20 Pages: 201402-201402

    • DOI

      10.1103/physrevb.81.201402

    • Related Report
      2013 Final Research Report
    • Peer Reviewed
  • [Journal Article] Dirac Fermions in Graphene Nanodisk and Graphene Corner : Texture of vortices with an unusual winding number2010

    • Author(s)
      M.Ezawa
    • Journal Title

      Physical Review B (rapid communications)

      Volume: 81

    • Related Report
      2010 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Giant Skyrmions Stabilized by Dipole-Dipole Interactions in Thin Ferromagnetic Films2010

    • Author(s)
      M.Ezawa
    • Journal Title

      Physical Review Letters

      Volume: 105

    • Related Report
      2010 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Manipulation of Two Spin Qubits in a Double Quantum Dot using an Electric Field2010

    • Author(s)
      Atsuo Shitade, Motohiko Ezawa, Naoto Nagaosa
    • Journal Title

      Physical Review B

      Volume: 82

    • Related Report
      2010 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Current Modulator based on Topological Insulator with Sliding Magnetic Superlattice2010

    • Author(s)
      M Ezawa, J.Zang
    • Journal Title

      Physical Review B

      Volume: 81

    • Related Report
      2010 Annual Research Report
    • Peer Reviewed
  • [Presentation] Quantum Anomalous Hall Effects and Topologcial Phase Transitions in Silicene2013

    • Author(s)
      M. Ezawa
    • Organizer
      APS2013 March Meeting 18-22 Baltimore Convention Center Baltimore
    • Place of Presentation
      Maryland, USA
    • Year and Date
      2013-03-19
    • Related Report
      2013 Final Research Report
    • Invited
  • [Presentation] シリセンpn接合の輸送理論2013

    • Author(s)
      山影相, 江澤雅彦, 田仲由喜夫, 永長直人
    • Organizer
      日本物理学会, 第68回年次大会
    • Place of Presentation
      広島大学 東広島キャンパス
    • Related Report
      2013 Final Research Report
  • [Presentation] Engineering topological phase transitions in silicene (oral presentation) QS2C Theory Forum2013

    • Author(s)
      M. Ezawa
    • Organizer
      International Symposium on "Strongly Correlated Quantum Science"
    • Place of Presentation
      The Univ. of Tokyo, Tokyo, Japan
    • Related Report
      2013 Final Research Report
  • [Presentation] Valley Dependent Physics in Silicene, energy materials nanotechnology2013

    • Author(s)
      M. Ezawa
    • Place of Presentation
      Houston, USA
    • Related Report
      2013 Final Research Report
    • Invited
  • [Presentation] Quantum Anomalous Hall Effects and Topologcial Phase Transitions in Silicene2013

    • Author(s)
      Motohiko Ezawa
    • Organizer
      APS2013 March Meeting
    • Place of Presentation
      Baltimore Convention Center Baltimore, Maryland March (2013)
    • Related Report
      2012 Annual Research Report
    • Invited
  • [Presentation] Valley Dependent Physics in Silicene2013

    • Author(s)
      Motohiko Ezawa
    • Organizer
      EMN west meeting, energy materials nanotechnology
    • Place of Presentation
      Houston USA
    • Related Report
      2012 Annual Research Report
    • Invited
  • [Presentation] シリセンpn接合の輸送理論2013

    • Author(s)
      山影相,江澤雅彦,田仲由喜夫,永長直人
    • Organizer
      第68回年次大会
    • Place of Presentation
      広島大学
    • Related Report
      2012 Annual Research Report
  • [Presentation] シリセンにおけるトポロジカル絶縁体2012

    • Author(s)
      江澤雅彦
    • Organizer
      日本物理学会2012年秋季大会
    • Place of Presentation
      横浜国立大学
    • Year and Date
      2012-09-20
    • Related Report
      2013 Final Research Report 2012 Annual Research Report
  • [Presentation] グラフェンナノ構造の電気的磁気的性質の理論的研究2012

    • Author(s)
      江澤雅彦
    • Organizer
      日本物理学会2012年年次大会にて若手奨励賞受賞記念講演
    • Place of Presentation
      関西学院大
    • Year and Date
      2012-03-27
    • Related Report
      2013 Final Research Report
  • [Presentation] Silicene : Silicon-based topological material (oral presentation)International Symposium2012

    • Author(s)
      M. Ezawa
    • Organizer
      "Nanoscience and Quantum Physics 2012" (nanoPHYS'12)
    • Place of Presentation
      Roppongi, Tokyo, Japan
    • Related Report
      2013 Final Research Report
  • [Presentation] シリセンにおけるトポロジカル相転移2012

    • Author(s)
      江澤雅彦
    • Organizer
      第6回物性科学領域横断研究会 (領域合同研究会)
    • Place of Presentation
      本郷, 東京
    • Related Report
      2013 Final Research Report
  • [Presentation] Topological Insulators in Silicene : Quantum Hall, Quantum Spin Hall and Quantum Anomalous Hall Effects (oral presentation)2012

    • Author(s)
      M. Ezawa
    • Organizer
      31st International Conference on the Physics of Semiconductors
    • Place of Presentation
      Zurich, Switzerland
    • Related Report
      2013 Final Research Report
  • [Presentation] シリセンにおけるトポロジカル相転移2012

    • Author(s)
      江澤雅彦
    • Organizer
      第6回 物性科学領域横断研究会 (領域合同研究会)
    • Place of Presentation
      東京大学
    • Related Report
      2012 Annual Research Report
  • [Presentation] Giant Skyrmions and Compact Merons in Thin Ferromagnetic Films2011

    • Author(s)
      M.Ezawa
    • Organizer
      Novel Quantum States in Condensed Matter 2011
    • Place of Presentation
      Kyoto
    • Year and Date
      2011-11-16
    • Related Report
      2011 Annual Research Report
  • [Presentation] Giant Skyrmions and Compact Merons in Thin Ferromagnetic Films (oral presentation) Novel Quantum States2011

    • Author(s)
      M. Ezawa
    • Organizer
      Condensed Matter 2011 (NQS2011)
    • Place of Presentation
      Kyoto, Japan
    • Related Report
      2013 Final Research Report
  • [Presentation] 三角グラフェンのDirac 理論と特異な渦構造2010

    • Author(s)
      江澤雅彦
    • Organizer
      日本物理学会2010年秋季大会
    • Place of Presentation
      大阪府立大学中百舌鳥キャンパス
    • Year and Date
      2010-09-24
    • Related Report
      2013 Final Research Report
  • [Presentation] 二重量子ドットにおけるスピンの電気的制御2010

    • Author(s)
      下出敦夫, 江澤雅彦, 永長直人
    • Organizer
      日本物理学会2010年秋季大会
    • Place of Presentation
      大阪府立大学中百舌鳥キャンパス
    • Year and Date
      2010-09-24
    • Related Report
      2013 Final Research Report
  • [Presentation] 強磁性薄膜中のスキルミオンとメロン2010

    • Author(s)
      江澤雅彦
    • Organizer
      第4回物性科学領域横断研究会
    • Place of Presentation
      本郷, 東京
    • Related Report
      2013 Final Research Report
  • [Presentation] Graphene Nanodisks : Nanomagnets made of Graphene, (oral presentation)2010

    • Author(s)
      M. Ezawa
    • Organizer
      Asian Conference on Nanoscience & Nanotechnology
    • Place of Presentation
      Odaiba, Japan
    • Related Report
      2013 Final Research Report
  • [Presentation] Giant Skyrmion in Thin Ferromagnetic Film : The impotance of Magnetic Dipole-Dipole interaction (poster presentation)2010

    • Author(s)
      M. Ezawa
    • Organizer
      2010 Opening Symposium of QS2C Theory Forum
    • Place of Presentation
      RIKEN, Japan
    • Related Report
      2013 Final Research Report
  • [Presentation] Quasiferromagnetism and Spintronics in Trigonal Graphene, (poster presentation)2010

    • Author(s)
      M. Ezawa
    • Organizer
      The 6th Internationla Conference on the Physics and Applications of Spin Related Phenomena in Semiconductors
    • Place of Presentation
      Tokyo, Japan
    • Related Report
      2013 Final Research Report
  • [Presentation] Peculiar Vortex Structure with Unusual Winding Number in Trigonal Graphene, (oral presentation)2010

    • Author(s)
      M. Ezawa
    • Organizer
      30th International Conference on the Physics of Semiconductors
    • Place of Presentation
      Seoul, Korea
    • Related Report
      2013 Final Research Report
  • [Presentation] Peculiar Vortex Structure with Unusual Winding Number in Trigonal Graphene2010

    • Author(s)
      M.Ezawa
    • Organizer
      30th International Conference on the Physics of Semiconductors
    • Place of Presentation
      Seoul, Korea
    • Related Report
      2010 Annual Research Report
  • [Presentation] Quasiferromagnetism and Spintronics in Trigonal Graphene2010

    • Author(s)
      M.Ezawa
    • Organizer
      The 6th Internationla Conference on the Physics and Applications of Spin Related Phenomena in Semiconductors
    • Place of Presentation
      Hongo, Tokyo, Japan
    • Related Report
      2010 Annual Research Report
  • [Presentation] Giant Skyrmion in Thin Ferromagnetic Film : The impotance of Magnetic Dipole-Dipole interaction2010

    • Author(s)
      M.Ezawa
    • Organizer
      2010 Opening Symposium of QS2C Theory Forum
    • Place of Presentation
      RIKEN, wako, saitama
    • Related Report
      2010 Annual Research Report
  • [Presentation] Graphene Nanodisks : Nanomagnets made of Graphene2010

    • Author(s)
      M.Ezawa
    • Organizer
      Asian Conference on Nanoscience & Nanotechnology
    • Place of Presentation
      Odaiba, Tokyo, Japan
    • Related Report
      2010 Annual Research Report
  • [Book] Physics of Triangular Graphene, Physics and Applications of Graphene -Theory, Sergey Mikhailov (Ed.)2011

    • Author(s)
      Motohiko Ezawa
    • Related Report
      2013 Final Research Report
  • [Book] Physics and Applications of Graphene-Theory (Physica of Triangular Graphene)2011

    • Author(s)
      M.Ezawa
    • Total Pages
      34
    • Publisher
      Intech
    • Related Report
      2011 Annual Research Report
  • [Remarks]

    • URL

      http://park.itc.u-tokyo.ac.jp/nagaosa-lab/ezawa/profile.html

    • Related Report
      2013 Final Research Report
  • [Remarks]

    • URL

      http://park.itc.u-tokyo.ac.jp/nagaosa-lab/ezawa/papers.html

    • Related Report
      2013 Final Research Report

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Published: 2010-08-23   Modified: 2020-05-15  

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