不揮発性抵抗変化メモリの動作機構解明と集積化への展開

• Project Area: Molecular Architectonics: Orchestration of Single Molecules for Novel Function
• Project/Area Number: 16H00952
• 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: Hokkaido University
• Principal Investigator: 中山 哲 北海道大学, 触媒科学研究所, 准教授 (10422007)
• Project Period (FY): 2016-04-01 – 2018-03-31
• Project Status: Completed (Fiscal Year 2017)
• Budget Amount: ¥5,720,000 (Direct Cost: ¥4,400,000、Indirect Cost: ¥1,320,000); Fiscal Year 2017: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000); Fiscal Year 2016: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
• Keywords: 第一原理計算 / 抵抗変化型メモリ / 第一原理シミュレーション / 不揮発性抵抗変化メモリ / ReRAM

Outline of Annual Research Achievements

不揮発性抵抗変化型ランダムアクセスメモリ（ReRAM）は抵抗変化が高速であり、大きな抵抗変化比を保ったまま微細加工できるために次世代メモリとして期待されている。酸化物（Ox）を金属電極（M）で挟んだM－Ox－M構造における抵抗スイッチ効果を利用したメモリの研究開発が活発に行われており、本研究では、第一原理計算によって、その伝導パスの形成過程と動作機構に着目した計算を行った。
本年度は、前年度までのタンタル酸化物を用いた抵抗変化メモリに関する研究を引き続き行った。まずは、酸化物中の欠陥生成エネルギーと欠陥移動のエネルギー障壁を算出することで、欠陥の移動経路を特定した。次に、タンタル酸化物中の酸素濃度を変化させ、伝導パスの安定性について議論した。同じ酸素濃度の条件で、Ta-Ta結合ネットワークによって伝導パスが存在する構造と、ランダムに酸素原子を配置させた構造でエネルギーの比較を行い、伝導パスが形成されている方がエネルギー的に安定であることを示した。また、M－Ta2O5－M構造として、タンタル金属を電極としたモデル系を構築し、Accelerated MD法を用いて酸化物中の酸素イオンを電極側に移動させるシミュレーションを行った。この過程をSET/RESET動作とみなし、移動前後で大きな抵抗比を再現できることを示した。統計量を増やした上で抵抗スイッチングに必要な力の定量的算出を行い、移動前後の酸素欠陥分布の安定性についても議論した。

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

• [Journal Article] Thermally activated delayed fluorescence OLEDs with fully solution processed organic layers exhibiting nearly 10% external quantum efficiency (2017)
  • Author(s): Ken Albrecht, Kenichi Matsuoka, Daisuke Yokoyama, Yoshiya Sakai, Akira Nakayama, Katsuhiko Fujita, Kimihisa Yamamoto
  • Journal Title: Chemical Communications Volume: 53 Issue: 16 Pages: 2439-2442
  • DOI: 10.1039/c6cc09275f
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Photo-induced b-Elimination of 9-Fluorenylmethanol Leading to Dibenzofulvene (2017)
  • Author(s): H. Nageh, L. Zhao, A. Nakayama, J. Hasegawa, Y. Wang, and T. Nakano
  • Journal Title: Chem. Comm. Volume: 53 Issue: 60 Pages: 8431-8434
  • DOI: 10.1039/c7cc03297h
  • Peer Reviewed
• [Journal Article] Formation of a New, Strongly Basic Nitrogen Anion by Metal Oxide Modification (2017)
  • Author(s): M. Tamura, R. Kishi, A. Nakayama, Y. Nakagawa, J. Hasegawa, and K. Tomishige
  • Journal Title: J. Am. Chem. Soc. Volume: 139 Issue: 34 Pages: 11857-11867
  • DOI: 10.1021/jacs.7b05227
  • Peer Reviewed
• [Journal Article] Catalytic Cyclopropanation by Myoglobin Reconstituted with Iron Porphycene: Acceleration of Catalysis due to Rapid Formation of the Carbene Species (2017)
  • Author(s): K. Oohora, H. Meichin, L. Zhao, M. W. Wolf, A. Nakayama, J. Hasegawa, N. Lehnert, and T. Hayashi
  • Journal Title: J. Am. Chem. Soc. Volume: 139 Issue: 48 Pages: 17265-17268
  • DOI: 10.1021/jacs.7b10154
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] A DFT and multi-configurational perturbation theory study on O2 binding to a model heme compound via the spin-change barrier (2016)
  • Author(s): Y. Kitagawa, Y. Chen, N. Nakatani, A. Nakayama, and J. Hasegawa
  • Journal Title: Phys. Chem. Chem. Phys. Volume: 18 Issue: 27 Pages: 18137-18144
  • DOI: 10.1039/c6cp02329k
  • NAID: 120006324911
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Spin-Blocking Effect in CO and H2 Binding Reactions to Molybdenocene and Tungstenocene: A Theoretical Study on the Reaction Mechanism via the Minimum Energy Intersystem Crossing Point (2016)
  • Author(s): K. Watanabe, N. Nakatani, A. Nakayama, M. Higashi, and J. Hasegawa
  • Journal Title: Inorg. Chem. Volume: 55 Issue: 16 Pages: 8082-8090
  • DOI: 10.1021/acs.inorgchem.6b01187
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Electronic Polarization Effect of the Water Environment in Charge-Separated Donor-Acceptor Systems: An Effective Fragment Potential Model Study (2016)
  • Author(s): K. Yanai, K. Ishimura, A. Nakayama, M. W. Schmidt, M. S. Gordon, and J. Hasegawa
  • Journal Title: J. Phys. Chem. A Volume: 120 Issue: 51 Pages: 10273-10280
  • DOI: 10.1021/acs.jpca.6b10552
  • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] A QM/MM Study of Absorption Spectra of Uracil Derivatives in Aqueous Solution (2016)
  • Author(s): A. Nakayama
  • Journal Title: AIP Conference Proceedings Volume: 1790 Pages: 020018-020018
  • DOI: 10.1063/1.4968644
  • Peer Reviewed / Acknowledgement Compliant
• [Presentation] Catalytic Reactions at the Liquid/CeO2 Interface: Role of the Acid-Base and Redox Sites (2018)
  • Author(s): A. Nakayama
  • Organizer: Pure and Applied Chemistry International Conference 2018 (PACCON 2018)
  • Int'l Joint Research / Invited
• [Presentation] Role of the Acid-Base and Redox Sites on Catalytic Reactions at the Liquid/CeO2 Interface (2018)
  • Author(s): A. Nakayama
  • Organizer: International Congress on Pure & Applied Chemistry (ICPAC) 2018
  • Int'l Joint Research / Invited
• [Presentation] 第一原理反応ダイナミクス計算による光機能性材料と不均一系触媒の理論的設計 (2018)
  • Author(s): 中山哲
  • Organizer: 日本化学会第98春季年会，中長期テーマシンポジウム
  • Invited
• [Presentation] 固体酸化物／液相界面における触媒反応 (2018)
  • Author(s): 中山哲
  • Organizer: 研究会「化学反応のポテンシャル曲面とダイナミックス」
  • Invited
• [Presentation] First-principles simulations of catalytic reactions at the liquid/CeO2 interface: role of the acid-base sites (2017)
  • Author(s): A. Nakayama
  • Organizer: International Symposium on Pure & Applied Chemistry (ISPAC) 2017
  • Int'l Joint Research / Invited
• [Presentation] Catalytic Reactions at the Liquid/Metal-Oxide Interface: Role of the Acid-Base Sites (2017)
  • Author(s): A. Nakayama
  • Organizer: The 21th International Annual Symposium on Computational Science and Engineering (ANSCSE 21)
  • Int'l Joint Research / Invited
• [Presentation] First-Principles Simulations of Catalytic Reactions at the Liquid/Ceria Interface (2017)
  • Author(s): A. Nakayama
  • Organizer: The 9th Conference of the Asian Consortium on Computational Materials Science (ACCMS-9)
  • Int'l Joint Research / Invited
• [Presentation] 第一原理計算による酸化セリウム触媒の機能解析 (2017)
  • Author(s): 中山哲
  • Organizer: 第120回触媒討論会
  • Invited
• [Presentation] Hydration of Nitriles at the Water/Metal-Oxide Interface: First-Principles Molecular Dynamics Simulations (2017)
  • Author(s): A. Nakayama
  • Organizer: EMN Meeting on Computation and Theory 2017
  • Int'l Joint Research / Invited
• [Presentation] Catalytic Reactions at the Water/CeO2 Interface: Hydration of 2-Cyanopyridine (2017)
  • Author(s): A. Nakayama, M. Tamura, K. Shimizu, and J. Hasegawa
  • Organizer: CPMD2017 Workshop
  • Int'l Joint Research
• [Presentation] Catalytic Reactions at the Water/CeO2 Interface: Hydration of 2-Cyanopyridine (2017)
  • Author(s): A. Nakayama, M. Tamura, K. Shimizu, and J. Hasegawa
  • Organizer: The 5th Ito International Research Conference, RIKEN Centennial Anniversary, ISSP International Workshop & Surface and Interface Spectroscopy 2017
  • Int'l Joint Research
• [Presentation] 酸化セリウム触媒の酸・塩基特性に関する理論的研究 (2016)
  • Author(s): 中山哲，田村正純，清水研一，長谷川淳也
  • Organizer: 第30回分子シミュレーション討論会
  • Place of Presentation: 大阪大学（大阪府豊中市）
  • Year and Date: 2016-11-30
• [Presentation] Catalytic reactions at the liquid/metal-oxide interface: role of the acid-base sites (2016)
  • Author(s): A. Nakayama
  • Organizer: Japan-France-Spain Joint Symposium on Theoretical and Computational Science of Complex Systems
  • Place of Presentation: 京都大学（京都府京都市）
  • Year and Date: 2016-10-26
  • Int'l Joint Research / Invited
• [Presentation] Catalytic Reactions at the Water/Ceria Interface: Role of the Acid-Base Sites (2016)
  • Author(s): A. Nakayama
  • Organizer: JST International Symposium on Multi-Scale Simulation of Condensed-Phase Reacting Systems (MSCRS2016)
  • Place of Presentation: 名古屋大学（愛知県名古屋市）
  • Year and Date: 2016-10-10
  • Int'l Joint Research / Invited
• [Presentation] 酸化セリウム触媒の酸・塩基特性に関する理論的研究 (2016)
  • Author(s): 中山哲，田村正純，清水研一，長谷川淳也
  • Organizer: 第118回触媒討論会
  • Place of Presentation: 岩手大学（岩手県盛岡市）
  • Year and Date: 2016-09-21
• [Presentation] Role of the Acid-Base Sites in Catalytic Reactions at the Water/CeO2(111) Interface: First-Principles Simulations (2016)
  • Author(s): A. Nakayama
  • Organizer: International Symposium on Pure & Applied Chemistry (ISPAC) 2016
  • Place of Presentation: クチン（マレーシア）
  • Year and Date: 2016-08-15
  • Int'l Joint Research / Invited
• [Presentation] First-Principles Simulations of Catalytic Reactions at the Water/CeO2(111) Interface: Role of the Acid-Base Sites (2016)
  • Author(s): A. Nakayama, M. Tamura, K. Shimizu, and J. Hasegawa
  • Organizer: ICC Pre-symposium of 16th International Congress on Catalysis
  • Place of Presentation: 北海道大学（北海道札幌市）
  • Year and Date: 2016-06-30
  • Int'l Joint Research