Twisted二層グラフェンにおける量子輸送現象

• Project Area: Frontiers of materials science spun from topology
• Project/Area Number: 16H00982
• 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: The University of Tokyo
• Principal Investigator: 増渕 覚 東京大学, 生産技術研究所, 特任講師 (50596195)
• Project Period (FY): 2016-04-01 – 2018-03-31
• Project Status: Completed (Fiscal Year 2017)
• Budget Amount: ¥5,200,000 (Direct Cost: ¥4,000,000、Indirect Cost: ¥1,200,000); Fiscal Year 2017: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000); Fiscal Year 2016: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000)
• Keywords: グラフェン / 複合原子層 / 量子ホール効果 / バンド構造変調 / ファンデルワールスヘテロ構造 / サイクロトロン共鳴 / 物性実験 / メゾスコピック系 / マイクロ・ナノデバイス / ナノ材料

Outline of Annual Research Achievements

本年度は、Twisted二層グラフェンにおける量子輸送現象解明に向けて、以下の研究を推進した。
・複合原子層作製作業の自動化：これまでTwisted二層グラフェンの作製作業は何れの研究室においても研究者の手作業により行われていた。研究の進展とともに、求められる素子構造が膨潤し、研究活動時間が圧迫される悪循環が生じていた。この問題を解決するため、ファンデルワールス接合構造の作製工程を自動化する自律ロボットシステムを開発した。本システムの利用により、1200枚の単層グラフェンを4時間で自動探索し、グラフェンとhBNを交互に8時間で30階積層することが可能となった。遷移金属カルコゲナイドも含む様々な二次元結晶が利用可能で、作製した素子は既存の最高品質素子に並ぶ高品質を示した。
・Twisted2層/3層グラフェンにおけるHofstadter's Butterflyの観測：自律ロボットシステムを用いることで結晶方位をTwistした2層/3層グラフェンを作製した。電気伝導特性評価を行ったところ、2層/3層グラフェンの結晶格子が構成するモアレ超格子の影響により、素子中に形成されたサブバンドに由来する電荷中性点が観測された。磁場を印加したところ、各サブバンドから生じるランダウ準位が交差したHofstadter's Butterflyを初めて観測した。現在、海外の理論研究グループと共同で実験データの解析を進めている。
・3層グラフェンにおけるランダウ準位反交差：Twist角制御による運動量空間におけるバンド構造変調の理解を深めるため、3層グラフェンを舞台として面内磁場印加による電子波動関数の運動量空間における平行シフトを導入した。単層グラフェン様バンドと2層グラフェン様バンド混成を実験・理論の両面から解明した。
・共同研究：ケンブリッジ大学・産業技術総合研究所に高品質試料の提供を行った。

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] University of Cambridge/National Physical Laboratory(United Kingdom)
• [Int'l Joint Research] Univ. Grenoble(France)
• [Int'l Joint Research] ENS-CNRS(France)
• [Journal Article] Autonomous robotic searching and assembly of two-dimensional crystals to build van der Waals superlattices (2018)
  • Author(s): Satoru Masubuchi, Masataka Morimoto, Sei Morikawa, Momoko Onodera, Yuta Asakawa, Kenji Watanabe, Takashi Taniguchi, Tomoki Machida
  • Journal Title: Nature Communications Volume: 9 Issue: 1 Pages: 1413-1413
  • DOI: 10.1038/s41467-018-03723-w
  • Peer Reviewed / Open Access
• [Journal Article] Imaging Bulk and Edge Transport near the Dirac Point in Graphene Moire 769; Superlattices (2018)
  • Author(s): Z. Dou, S. Morikawa, A. Cresti, S.-W. Wang, C. G. Smith, C. Melios, O. Kazakova, K. Watanabe, T. Taniguchi, S. Masubuchi, T. Machida, M. R. Connolly
  • Journal Title: Nano Lett. Volume: 18 Issue: 4 Pages: 2530-2537
  • DOI: 10.1021/acs.nanolett.8b00228
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Extremely large magnetoresistance in a high-quality WTe2 grown by flux method (2018)
  • Author(s): K. Tsumura, R. Yano, H. Kashiwaya, M. Koyanagi, S. Masubuchi, T. Machida, H. Namiki, T. Sasagawa and S. Kashiwaya
  • Journal Title: Journal of Physics: Conference Series Volume: 969 Pages: 012134-012134
  • DOI: 10.1088/1742-6596/969/1/012134
  • Peer Reviewed / Open Access
• [Journal Article] Intersubband Landau Level Couplings Induced by In-Plane Magnetic Fields in Trilayer Graphene (2017)
  • Author(s): Yuta Asakawa, Satoru Masubuchi, Naoko Inoue, Sei Morikawa, Kenji Watanabe, Takashi Taniguchi, and Tomoki Machida
  • Journal Title: Physical Review Letters Volume: 119 Issue: 18 Pages: 186802-186802
  • DOI: 10.1103/physrevlett.119.186802
  • Peer Reviewed
• [Journal Article] Suppression of exciton-exciton annihilation in tungsten disulfide monolayers encapsulated by hexagonal boron nitrides (2017)
  • Author(s): Yusuke Hoshi, Takashi Kuroda, Mitsuhiro Okada, Rai Moriya, Satoru Masubuchi, Kenji Watanabe, Takashi Taniguchi, Ryo Kitaura, and Tomoki Machida
  • Journal Title: Physical Review B Volume: 95 Issue: 24 Pages: 241403-241403
  • DOI: 10.1103/physrevb.95.241403
  • Peer Reviewed
• [Journal Article] Exfoliation and van der Waals heterostructure assembly of intercalated ferromagnet Cr1/3TaS2 (2017)
  • Author(s): Yuji Yamasaki, Rai Moriya, Miho Arai, Satoru Masubuchi, Sunseng Pyon, Tsuyoshi Tamegai, Keiji Ueno, Tomoki Machida
  • Journal Title: 2D Materials Volume: 4 Issue: 4 Pages: 041007-041007
  • DOI: 10.1088/2053-1583/aa8a2b
  • Peer Reviewed
• [Journal Article] Dirac fermion reflector by ballistic graphene sawtooth-shaped npn junctions (2017)
  • Author(s): S. Morikawa, Q. Wilmart S. Masubuchi, K. Watanabe, T. Taniguchi, B. Placais, and T. Machida
  • Journal Title: Semicondoctor Science and Technology, Volume: 32 Issue: 4 Pages: 045010-045010
  • DOI: 10.1088/1361-6641/aa6102
  • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] N- and p-type carrier injections into WSe2 with van der Waals contacts of two-dimensional materials (2017)
  • Author(s): Yohta Sata, Rai Moriya, Satoru Masubuchi, Kenji Watanabe, Takashi Taniguchi, Tomoki Machida
  • Journal Title: Japanese Journal of Applied Physics Volume: 56 Issue: 4S Pages: 04CK09-04CK09
  • DOI: 10.7567/jjap.56.04ck09
  • NAID: 210000147636
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Comparisons of magnetoresistance in triangular and rectangular ballistic graphene npn junctions (2016)
  • Author(s): S. Morikawa, S. Masubuchi, K. Watanabe, T. Taniguchi, and T. Machida
  • Journal Title: Japanese Journal of Applied Physics Volume: 55 Issue: 10 Pages: 100305-100305
  • DOI: 10.7567/jjap.55.100305
  • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
• [Presentation] ファンデルワールス超格子の自動作製 ：ロボットによる二次元層状物質の劈開・探索・積層 (2018)
  • Author(s): 増渕覚, 森本将崇, 小野寺桃子, 森川生, 渡邊賢司, 谷口尚, 町田友樹
  • Organizer: 日本物理学会2018年春季大会
• [Presentation] ファンデルワールス超格子の自動作製：ロボットによる二次元層状物質の劈開・探索・積層 (2018)
  • Author(s): 増渕覚, 森本将崇, 小野寺桃子, 森川生, 渡邊賢司, 谷口尚, 町田友樹
  • Organizer: 第65回 応用物理学会 春季学術講演会
• [Presentation] Automated searching and assembly of atomic layers: a robotic building system of van der Waals superlattices (2018)
  • Author(s): Satoru Masubuchi, Masataka Morimoto, Momoko Onodera, Sei Morikawa, Kenji Watanabe, Takashi Taniguchi, and Tomoki Machida
  • Organizer: 第54回 フラーレン・ナノチューブ・グラフェン 総合シンポジウム
• [Presentation] Inter-subband Landau level couplings induced by in-plane magnetic fields in trilayer graphene (2018)
  • Author(s): S Masubuchi, Y Asakawa, N Inoue, K Watanabe, T Taniguchi, T Machida
  • Organizer: American Physical Society March Meeting
  • Int'l Joint Research
• [Presentation] Automated searching and assembly of atomic layers: a robotic building system of van der Waals superlattices (2018)
  • Author(s): Satoru Masubuchi, Masataka Morimoto, Momoko Onodera, Sei Morikawa, Kenji Watanabe, Takashi Taniguchi, Tomoki Machida
  • Organizer: American Physical Society March Meeting
• [Presentation] Imaging Bulk and Edge Transport near the Dirac Point in Graphene Moire Superlattices (2018)
  • Author(s): Ziwei Dou, Sei Morikawa, Alessandro Cresti, Shu-Wei Wang, Charles G. Smith, Christos Melios, Olga Kazakova, Kenji Watanabe, Takashi Taniguchi, Satoru Masubuchi, Tomoki Machida, and Malcolm R. Connolly
  • Organizer: American Physical Society March Meeting
  • Int'l Joint Research
• [Presentation] グラフェンpn接合でのサイクロトロン共鳴による光起電力測定 (2018)
  • Author(s): 木下 圭、守谷 頼、荒井 美穂、増渕 覚、渡邊 賢司、谷口 尚、町田 友樹
  • Organizer: 第65回 応用物理学会 春季学術講演会
• [Presentation] グラフェン/hBN/グラフェンvan der Waalsヘテロ接合におけるトンネル効果 (2018)
  • Author(s): 瀬尾優太, 増渕覚, 小野寺桃子, 渡邊賢司, 谷口尚, 町田友樹
  • Organizer: 日本物理学会2018年春季大会
• [Presentation] Tunneling transport between monolayer graphene and bilayer graphene in high magnetic fields (2018)
  • Author(s): Momoko Onodera, Sei, Morikawa, Satoru Masubuchi, Kenji Watanabe, Takashi Taniguchi, Tomoki Machida
  • Organizer: Graphene Weeks 2017
  • Int'l Joint Research
• [Presentation] 面内磁場の誘起するABA三層グラフェンのランダウ準位反交差 (2017)
  • Author(s): 浅川友太、増渕覚、井上尚子、森川生、渡邊賢司、谷口 尚、町田友樹
  • Organizer: 日本物理学会第72回年次大会、17pB21-4、大阪大学、大阪 (2016).
  • Place of Presentation: 大阪大学、大阪
  • Year and Date: 2017-03-17
• [Presentation] Automated searching and assembly of atomic layers: a robotic building system of van der Waals superlattices (2017)
  • Author(s): Satoru Masubuchi, Masataka Morimoto, Momoko Onodera, Sei Morikawa, Kenji Watanabe, Takashi Taniguchi, Tomoki Machida
  • Organizer: Graphene Weeks 2017
  • Int'l Joint Research
• [Presentation] Imaging Bulk and Edge Transport near the Dirac Point in Graphene Moire Superlattices (2017)
  • Author(s): Ziwei Dou, Sei Morikawa, Alessandro Cresti, Shu-Wei Wang, Charles G. Smith, Christos Melios, Olga Kazakova, Kenji Watanabe, Takashi Taniguchi, Satoru Masubuchi, Tomoki Machida, and Malcolm R. Connolly
  • Organizer: Graphene Weeks 2017
  • Int'l Joint Research
• [Presentation] 三層グラフェンにおけるランダウ準位交差・反交差の観測 (2016)
  • Author(s): 増渕 覚、浅川友太、井上尚子、森川 生、渡邊賢司、谷口 尚、町田友樹
  • Organizer: 第30回ダイヤモンドシンポジウム、P2-24、東京大学駒場リサーチキャンパス、東京 (2016).
  • Place of Presentation: 東京大学生産技術研究所、東京
  • Year and Date: 2016-11-17
• [Presentation] Tunnel magnetoresistance effect in van der Waals junction built from layered material ferromagnets (2016)
  • Author(s): R. Moriya, M. Arai, Y. Yamasaki, S. Masubuchi, K. Ueno, and T. Machida
  • Organizer: 9th International Conference on Physics and Applications of Spin-Related Phenomena in Solids (PASPS9), P1-28, Kobe-city, Japan (2016).
  • Place of Presentation: Kobe, Japan
  • Year and Date: 2016-10-21
  • Int'l Joint Research
• [Presentation] Influence of substrate interaction on the optical properties of hBN/WS2 van der Waals heterostructures (2016)
  • Author(s): Y. Hoshi, R. Moriya, M. Arai, S. Masubuchi, T. Kuroda, K. Watanabe, T. Taniguchi, and T. Machida
  • Organizer: The 22nd International Conference on High Magnetic Fields in Semiconductor Physics (HMF-22), Mo-B-2, Hokkaido, Japan (2016).
  • Place of Presentation: Hokkaido, Japan
  • Year and Date: 2016-07-26
  • Int'l Joint Research
• [Presentation] Enhancement of resistance in ballistic graphene sawtoogh-shaped npn junctions (2016)
  • Author(s): S. Morikawa, Q. Wilmart, S. Masubuchi, K. Watanabe, T. Taniguchi, B. Placais, and T. Machida
  • Organizer: The 22nd International Conference on High Magnetic Fields in Semiconductor Physics (HMF-22), Mo-B-2, Hokkaido, Japan (2016).
  • Place of Presentation: Hokkaido, Japan
  • Year and Date: 2016-07-26
  • Int'l Joint Research
• [Presentation] Van der Waals assembly of layered ferromagnetic dichalcogenide (2016)
  • Author(s): M. Arai, Y. Yamasaki, R. Moriya, S. Masubuchi, K. Ueno, and T. Machida
  • Organizer: The 22nd International Conference on High Magnetic Fields in Semiconductor Physics (HMF-22), Mo-B-2, Hokkaido, Japan (2016).
  • Place of Presentation: Hokkaido, Japan
  • Year and Date: 2016-07-26
  • Int'l Joint Research
• [Presentation] Quantum Hall effect in a slightly twisted bilayer graphene (2016)
  • Author(s): S. Masubuchi, N. Inoue, Y. Asakawa, R. Kashiwagi, S. Morikawa, K. Watanabe, T. Taniguchi, and T. Machida
  • Organizer: The 22nd International Conference on High Magnetic Fields in Semiconductor Physics (HMF-22), Mo-B-2, Hokkaido, Japan (2016).
  • Place of Presentation: Hokkaido, Japan
  • Year and Date: 2016-07-25
  • Int'l Joint Research
• [Presentation] Observation of crossings and anti-crossings of subband levels in bernal trilayer graphene (2016)
  • Author(s): Y. Asakawa, S. Masubuchi, N. Inoue, S. Morikawa, K. Watanabe, T. Taniguchi, and T. Machida
  • Organizer: The 22nd International Conference on High Magnetic Fields in Semiconductor Physics (HMF-22), Mo-B-2, Hokkaido, Japan (2016).
  • Place of Presentation: Hokkaido, Japan
  • Year and Date: 2016-07-25
  • Int'l Joint Research
• [Presentation] Josephson effect in van der Waals junctions of 2D layered superconductors (2016)
  • Author(s): T. Machida, R. Moriya, N. Yabuki, M. Arai, Y. Sata, S. Morikawa, and S. Masubuchi
  • Organizer: Graphene Week 2016, Warsaw, Poland (2016).
  • Place of Presentation: Warsaw, Poland
  • Year and Date: 2016-06-15
  • Int'l Joint Research
• [Presentation] Tunnel magnetoresistance effect in van der Waals junction composed of layered material ferromagnets (2016)
  • Author(s): Y. Yamasaki, M. Arai, R. Moriya, S. Masubuchi, K. Ueno, and T. Machida
  • Organizer: Graphene Week 2016, Warsaw, Poland (2016).
  • Place of Presentation: Warsaw, Poland
  • Year and Date: 2016-06-15
  • Int'l Joint Research
• [Presentation] Observation of Subband Landau Level Crossings and Anticrossings in Bernal Trilayer Graphene (2016)
  • Author(s): Y. Asakawa, S. Masubuchi, N. Inoue, S. Morikawa, K. Watanabe, T. Taniguchi, and T. Machida
  • Organizer: Graphene Week 2016, Warsaw, Poland (2016).
  • Place of Presentation: Warsaw, Poland
  • Year and Date: 2016-06-15
  • Int'l Joint Research
• [Presentation] Manipulation of ballistic carrier trajectories in graphene by triangular shape npn junctions (2016)
  • Author(s): S. Morikawa, Q. Wilmart, S. Masubuchi, K. Watanabe, T. Taniguchi, B. Placais, and T. Machida
  • Organizer: Graphene Week 2016, Warsaw, Poland (2016).
  • Place of Presentation: Warsaw, Poland
  • Year and Date: 2016-06-14
  • Int'l Joint Research
• [Presentation] Imaging ballisitc and non-local transport in graphene using scanning gate microscopy (2016)
  • Author(s): Z. Dou, S. Morikawa, S. W. Wang, C. G. Smith, K. Watabe, T. Taniguchi, S. Masubuchi, T. Machida, and M. R. Connolly
  • Organizer: Graphene Week 2016, Warsaw, Poland (2016).
  • Place of Presentation: Warsaw, Poland
  • Year and Date: 2016-06-13
  • Int'l Joint Research
• [Patent(Industrial Property Rights)] Robotic building system of van der Waals superlattices (2018)
  • Inventor(s): Satoru Masubuchi, Tomoki Machida
  • Industrial Property Rights Holder: Satoru Masubuchi, Tomoki Machida
  • Industrial Property Rights Type: 特許
  • Filing Date: 2018
  • Overseas