第一原理有効模型と相関科学のフロンティア

2011 Fiscal Year Annual Research Report

• Project Area: Materials Design through Computics: Complex Correlation and Non-equilibrium Dynamics
• Project/Area Number: 22104010
• Research Institution: The University of Tokyo
• Principal Investigator: 今田 正俊 東京大学, 大学院・工学系研究科, 教授 (70143542)
• Co-Investigator(Kenkyū-buntansha): 三宅 隆 産業技術総合研究所, 計算科学研究部門, 主任研究員 (30332638) ; 中村 和磨 東京大学, 大学院・工学系研究科, 助教 (60525236) ; 佐久間 怜 千葉大学, 大学院・融合科学研究科, 助教 (10512204)
• Keywords: 第一原理計算 / 強相関電子系 / 有効模型 / 光電子分光 / スピン軌道相互作用 / 鉄系超伝導体 / 有機導体 / 非従来型超伝導

Research Abstract

密度汎関数法と強相関模型解法を融合し、従来の密度汎関数法では困難な強相関電子系を高精度、低負荷で取り扱える新手法を確立し、現実の多彩な物質群への広範な実証研究の展開を進めた。とりわけ鉄系超伝導体の電子状態を第一原理的に導出された4種の鉄系超伝導体(:LaFeAsO,LaFePO,BaFe2As2,FeTe)の有効模型に対して、多変数変分モンテカルロ法を適用して調べ、これら4つの物質の磁性に関する実験結果を再現することを示した。現実物質が巨大なモット絶縁体の辺縁部に位置することもわかった。またCa_4Al_2O_6Fe_2As_2の電子状態を解明し、不純物効果の微視的理解を目的として、LaFeAsOに対する不純物ポテンシャルの第一原理評価を行った。Ba_<1-x>KxFe_2As_2でx=0.4で全ての軌道が同等に超伝導に寄与していると考えられるのに対しx=1.0ではs±波超伝導となっていることを光電子分光で見出した。超伝導体の第一原理計算を芳香族超伝導体、フラーレン超伝導体、窒化物超伝導体で行ない、従来型超伝導としては理解できない要素を抽出した。スピン軌道相互作用の強い物質群の電子状態の解明も進め、Sr_2IrO_4、Ba_2IrO_4はスピン軌道相互作用と電子相関の相乗作用によって磁気秩序が生じてはじめて絶縁化するスレータ-絶縁体であることを明らかにした。Cd_2Os_2O_7へのLDA+U計算に着手し、現実的なUのパラメータ領域では反強磁性絶縁体で、all-in/all-out磁気構造が安定であること、強い磁気異角性(single-ion anisotropy)をもつことを見いだした。また水銀カルコゲナイドの研究に基づき、スピン軌道相互作用を取り入れたGW近似はトポロジカル絶縁体一般の準粒子バンド構造の定量計算ツールとして有望であることを示した。トポロジカル絶縁体の物理の理論と光電子分光の両面からの研究も進めている。多バンド強相関物質について角度分解光電子分光を行い,第一原理計算との比較から電子相関効果を議論した.

Current Status of Research Progress

1: Research has progressed more than it was originally planned.

Reason

当初の計画を超えて、MACE(第一原理強相関電子状態解明法)の適用が広範に進み、鉄系超伝導体、スピン軌道相互作用の強い物質などでの研究が大きく進展した。

Strategy for Future Research Activity

今後非平衡状態解明のための手法開発を進める。また光電子分光とMACEとの融合研究、トポロジカル絶縁体での興味ある物性の予測と設計を進める。

Research Products

• [Journal Article] Ab initio Studies on the Interplay between Spin-Orbit Interaction and Coulomb Correlation in Sr_2IrO_4 and Ba_2IrO_4 (2012)
  • Author(s): R.Arita, J.Kunes, A.V.Kozhevnikov, A.G.Eguiluz, M.Imada
  • Journal Title: Phys.Rev.Lett. Volume: 108 Pages: 086403(1-5)
  • DOI: DOI:10.1103/PhysRevLett.108.86403
  • Peer Reviewed
• [Journal Article] Mott Transition and Phase Diagram of κ-(BEDT-TTF)_2Cu(NCS)_2 Studied by Two-Dimensional Model Derived from Ab initio Method (2012)
  • Author(s): Hiroshi Shinaoka, Takahiro Misawa, Kazuma Nakamura, Masatoshi Imada
  • Journal Title: J.Phys.Soc.Jpn. Volume: 81 Pages: 034701(1-15)
  • DOI: DOI:10.1143/JPSJ.81.034701
  • Peer Reviewed
• [Journal Article] First-principles Electronic Structure of Superconductor Ca_4Al_2O_6Fe_2P_2 : Comparison with LaFePO and Ca_4Al_2O_6Fe_2As_2 (2012)
  • Author(s): Taichi Kosugi, Takashi Miyake, Shoji Ishibashi
  • Journal Title: J.Phys.Soc.Jpn. Volume: 81 Pages: 014701(1-7)
  • DOI: DOI:10.1143/JPSJ.81.014701
  • Peer Reviewed
• [Journal Article] Effects of transition-metal substitution in the iron-based superconductor LaFeAsO : Momentum- and real-space analysis from first principles (2012)
  • Author(s): S.Konbu, K.Nakamura, H.Ikeda, R.Arita
  • Journal Title: Solid State Communications Volume: 152 Pages: 728-734
  • DOI: DOI:10.1016/j.ssc.2011.12.048
  • Peer Reviewed
• [Journal Article] Magnetic Properties of Ab initio Model for Iron-Based Superconductors LaFeAsO (2011)
  • Author(s): Takahiro Misawa, Kazuma Nakamura, Masatoshi Imada
  • Journal Title: J.Phys.Soc.Jpn. Volume: 80 Pages: 023704(1-4)
  • DOI: DOI:10.1143/JPSJ.80.023704
  • Peer Reviewed
• [Journal Article] First-principles structural optimization and electronic structure of picene superconductor for various potassium-doping levels (2011)
  • Author(s): Taichi Kosugi, Takashi Miyake, Shoji Ishibashi, Ryotaro Arita, Hideo Aoki
  • Journal Title: Phys.Rev.B Volume: 84 Pages: 214506(1-8)
  • DOI: DOI:10.1103/PhysRevB.84.214506
  • Peer Reviewed
• [Journal Article] GW calculations with spin-orbit coupling : application to Hg chalcogenides (2011)
  • Author(s): R.Sakuma, C.Friedrich, T.Miyake, S.Blugel, F.Aryasetiawan
  • Journal Title: Phys.Rev.B Volume: 84 Pages: 085144(1-10)
  • DOI: DOI:10.1103/PhysRevB.84.085144
  • Peer Reviewed
• [Journal Article] Ab initio electronic structure of solid coronene : Differences from and commonalities to picene (2011)
  • Author(s): T.Kosugi, T.Miyake, S.Ishibashi, R.Arita, H.Aoki
  • Journal Title: Phys.Rev.B Volume: 84 Pages: 020507(R)(1-4)
  • DOI: DOI:10.1103/PhysRevB.84.020507
  • Peer Reviewed
• [Journal Article] Slab Thickness Dependence of Rashba Splitting on Au (111) surface : First-principles and Model Analyses (2011)
  • Author(s): Taichi Kosugi, Takashi Miyake, Shoji Ishibashi
  • Journal Title: J.Phys.Soc.Jpn. Volume: 80 Pages: 074713(1-7)
  • DOI: DOI:10.1143/JPSJ.80.074713
  • Peer Reviewed
• [Journal Article] Ab initio Derivation of Correlated Superatom Model for Potassium Loaded Zeolite A (2011)
  • Author(s): Yoshiro Nohara, Kazuma Nakamura, Ryotaro Arita
  • Journal Title: J.Phys.Soc.Jpn. Volume: 80 Pages: 124705(1-7)
  • DOI: DOI:10.1143/JPSJ.80.124705
  • Peer Reviewed
• [Journal Article] First-principles calculation of transition-metal impurities in LaFeAsO (2011)
  • Author(s): Kazuma Nakamura, Ryotaro Arita, Hiroaki Ikeda
  • Journal Title: Phys.Rev.B Volume: 83 Pages: 144512(1-9)
  • DOI: DOI:10.1103/PhysRevB.83.144512
  • Peer Reviewed
• [Journal Article] Fermi-Suface Evolution by Transition-Metal Substitution in the Iron-based Superconductor LaFeAsO (2011)
  • Author(s): S.Konbu, K.Nakamura, H.Ikeda, R.Arita
  • Journal Title: J.Phys.Soc.Jpn. Volume: 80 Pages: 123701(1-4)
  • DOI: DOI:10.1143/JPSJ.80.123701
  • Peer Reviewed
• [Journal Article] Conduction-band electronic states of YbInCu4 studied by photoemission and soft x-ray absorption spectroscopies (2011)
  • Author(s): Y.Utsumi, H.Sato, H.Kurihara, H.Maso, K.Hiraoka, K.Kojima, K.Tobimatsu, T.Ohkochi, S.Fujimori, Y.Takeda, Y.Saitoh, K.Mimura, S.Ueda, Y.Yamashita, H.Yoshikawa, K.Kobayashi, T.Oguchi, K.Shimada, H.Namatame, M.Taniguchi
  • Journal Title: Phys.Rev.B Volume: 84 Pages: 115143(1-7)
  • DOI: DOI:10.1103/PhysRevB.84.115143
  • Peer Reviewed
• [Journal Article] Role of van der Waals interaction in crystalline ammonia borane (2011)
  • Author(s): K.Yamauchi, I.Hamada, H.B.Huang, T.Oguchi
  • Journal Title: Appl.Phys.Lett. Volume: 99 Pages: 181904(1-3)
  • DOI: DOI:10.1063/1.3657526
  • Peer Reviewed
• [Journal Article] Two- and three-dimensional Fermi surfaces and their nesting properties in superconducting BaFe_2(As_<1-x>P_x)_2 (2011)
  • Author(s): T.Yoshida. I.Nishi, S.Ideta, A.Fujimori, M.Kubota, K.Ono, S.Kasahara, T.Shibauchi, T.Terashima, Y.Matsuda, H.Ikeda, R.Arita
  • Journal Title: Phys.Rev.Lett. Volume: 106 Pages: 117001(1-4)
  • DOI: DOI:10.1103/PhysRevLett.106.117001
  • Peer Reviewed
• [Journal Article] Orbital-Independent Superconducting Gaps in Iron Pnictides (2011)
  • Author(s): T.Shimojima, F.Sakaguchi, K.Ishizaka, Y.Ishida, T.Kiss, M.Okawa, T.Togashi, C.-T.Chen, S.Watanabe, M.Arita, K.Shimada, H.Namatame, M.Taniguchi, K.Ohgushi, S.Kasahara, T.Terashima, T.Shibauchi, Y.Matsuda, A.Chainani, S.Shin
  • Journal Title: Science Volume: 332 Pages: 564-567
  • DOI: DOI:10.1126/science.1202150
  • Peer Reviewed
• [Journal Article] Two-Fermi-Surface Superconducting State and a Nodal d-Wave Energy Gap of the Electron-Doped Sm1.85Ce0.15CuO4-□ Cuprate Superconductor (2011)
  • Author(s): A.F.Santander-Syro, M.Ikeda, T.Yoshida, A.Fujimori, K.Ishizaka, M.Okawa, S.Shin, B.Liang, A.Zimmers, R.L.Greene, N.Bontemps
  • Journal Title: Phys.Rev.Lett. Volume: 106 Pages: 197002(1-4)
  • DOI: DOI:10.1103/PhysRevLett.106.197002
  • Peer Reviewed
• [Journal Article] Giant Rashba-type spin splitting in bulk BiTeI (2011)
  • Author(s): K.Ishizaka, M.S.Bahramy, H.Murakawa, M.Sakano, T.Shimojima, T.Sonobe, K.Koizumi, S.Shin, H.Miyahara, A.Kimura, K.Miyamoto, T.Okuda, H.Namatame, M.Taniguchi, R.Arita, N.Nagaosa, K.Kobayashi, Y.Murakami, R.Kumai, Y.Kaneko, Y.Onose, Y.Tokura
  • Journal Title: Nature Mater. Volume: 10 Pages: 521-526
  • DOI: DOI:10.1038/nmat3051
  • Peer Reviewed
• [Journal Article] Common Origin of the Circular-Dichroism Pattern in Angle-Resolved PhotoemissionSpectroscopy of SrTiO_3 and Cu_xBi_2Se_3 (2011)
  • Author(s): Y.Ishida, H.Kanto, A.Kikkawa, Y.Taguchi, Y.Ito, Y.Ota, K.Okazaki, W.Malaeb, M.Mulazzi, M.Okawa, S.Watanabe, C.-T.Chen, M.Kim, C.Bell, Y.Kozuka, H.Y.Hwang, Y.Tokura, S.Shin
  • Journal Title: Phys.Rev.Lett. Volume: 107 Pages: 077601(1-4)
  • DOI: DOI:10.1103/PhysRevLett.107.077601
  • Peer Reviewed
• [Journal Article] Non-thermal hot electrons ultrafastly generating hot optical phonons in graphite (2011)
  • Author(s): Y.Ishida, T.Togashi, K.Yamamoto, M.Tanaka, T.Taniuchi, T.Kiss, M.Nakajima, T.Suemoto, S.Shin
  • Journal Title: Sci.Rep. Volume: 1 Pages: 64(1-5)
  • DOI: DOI:10.1038/srep00064
  • Peer Reviewed
• [Journal Article] Orbital characters of three-dimensional Fermi surfaces in Eu2-xSrxNiO4 as probed by soft-x-ray angle-resolved photoemission spectroscopy (2011)
  • Author(s): M.Uchida, K.Ishizaka, P.Hansmann, X.Yang, M.Sakano, J.Miyawaki, R.Arita, Y.Kaneko, Y.Takata, M.Oura, A.Toschi, K.Held, A.Chainani, O.K.Andersen, S.Shin, Y.Tokura
  • Journal Title: Phys.Rev.B Volume: 84 Pages: 241109(R)(1-5)
  • DOI: DOI:10.1103/PhysRevB.84.241109
  • Peer Reviewed
• [Presentation] Interplay between Spin-Orbit Interaction and Coulomb Correlation in Sr2IrO4 and Ba2IrO4 (2012)
  • Author(s): Ryotaro Arita
  • Organizer: RIKEN-APW-joint workshop Recent trends in condensed matter physics
  • Place of Presentation: Wako, Japan(招待講演)
  • Year and Date: 20120614-20120616
• [Presentation] Time-resolved ARPES of graphite using deep-to-extreme UV lasers (2012)
  • Author(s): Y.Ishida
  • Organizer: JAEA Symposium on Synchrotron Radiation Research
  • Place of Presentation: Public Relations Center of SPring-8, Hyogo(招待講演)
  • Year and Date: 20120307-20120309
• [Presentation] Dynamically screened Coulomb interaction and GW self-energy in transition metal compounds (2012)
  • Author(s): T.Miyake
  • Organizer: Frontiers of Electronic Structure Theory : Strong Correlations from First Principles" in the spring meeting of the German Physical Society
  • Place of Presentation: Berlin, Germany(招待講演)
  • Year and Date: 2012-03-30
• [Presentation] 第一原理電子状態計算による鉄系超伝導体関連物質の研究 (2012)
  • Author(s): 石橋章司
  • Organizer: 日本物理学会第67回年次大会
  • Place of Presentation: 関西学院大学、西宮市(招待講演)
  • Year and Date: 2012-03-27
• [Presentation] Mechanism of high Tc superconductivity in layered nitride superconductors : Insights from DFT for superconductors (2011)
  • Author(s): Ryotaro Arita
  • Organizer: Novel Quantum States in Condensed Matter 2011 (NQS2011)
  • Place of Presentation: Kyoto, Japan(招待講演)
  • Year and Date: 20111205-20111209
• [Presentation] Variational Monte Carlo study of strongly correlated electron systems (2011)
  • Author(s): Takahiro Misawa
  • Organizer: Japan-Swiss Workshop, New Electronic Properties through Structure and Correlation
  • Place of Presentation: Swiss ETH(招待講演)
  • Year and Date: 20110916-20110918
• [Presentation] Present status of Soft X-ray RIXS in SPring-8 ; electronic structure of liquids and protein (2011)
  • Author(s): S.Shin
  • Organizer: Workshop on Resonant Inelastic and Elastic X-Ray Scattering
  • Place of Presentation: SLS, PSI, Switzerland(招待講演)
  • Year and Date: 20110916-20110917
• [Presentation] Mechanism of high Tc superconductivity in layered nitride superconductors : Insights from DFT for superconductors (2011)
  • Author(s): Ryotaro Arita
  • Organizer: Tokyo-Cologne Workshop on Strongly Correlated Transition-Metal Compounds
  • Place of Presentation: Cologne, Germany(招待講演)
  • Year and Date: 20110907-20110909
• [Presentation] Fermi surfaces, electron correlation, and superconducting gaap in Fepnictides studied by ARPES (2011)
  • Author(s): A.Fujimori
  • Organizer: Workshop on Search for New Physics in Transition Metal Compounds by Spectroscopies
  • Place of Presentation: Institute for Materials Research (IMR), Tohoku University, Sendai(招待講演)
  • Year and Date: 20110728-20110730
• [Presentation] Laser-ARPES study on Fe-pnictide superconductors (2011)
  • Author(s): S.Shin
  • Organizer: International Workshop on Strong Correlations and Angle-Resolved Photoemission Spectroscopy (CORPES11)
  • Place of Presentation: Berkeley, California, USA(招待講演)
  • Year and Date: 20110718-20110722
• [Presentation] Three-dimensional Fermi surfaces and their nesting properties in the iron pnictide superconductor BaFe_2(As_<1-x>P_x)_2 (2011)
  • Author(s): T.Yoshida
  • Organizer: 8th International Conference on Stripes and High Tc Superconductivity (STRIPES 11)
  • Place of Presentation: Rome, Italy(招待講演)
  • Year and Date: 20110710-20110716
• [Presentation] Impurity effects in iron-based superconductors (2011)
  • Author(s): Ryotaro Arita
  • Organizer: Ringberg Symposium on High Temperature Superconductivity
  • Place of Presentation: Schloss Ringberg, Germany(招待講演)
  • Year and Date: 20110516-20110519
• [Presentation] Design of d1, d7, and J=1/2 analogs of cuprates from first principles (2011)
  • Author(s): Ryotaro Arita
  • Organizer: KIAS workshop on Frontiers in Condensed matter physics
  • Place of Presentation: Korea institute for advanced study, Korea(招待講演)
  • Year and Date: 20110509-20110512
• [Presentation] Ab initio low-energy models in iron-based supeconductors studied by variational Monte Carlo method : Role of electron correlation and origin of small magnetic ordered moment m LaFeAsO (2011)
  • Author(s): Takahiro Misawa
  • Organizer: Villa Conference on Iron Pnictide Superconductors
  • Place of Presentation: Las Vegas, USA(招待講演)
  • Year and Date: 20110421-20110425
• [Presentation] Topological transitions and topological insulators (2011)
  • Author(s): Masatoshi Imada
  • Organizer: The 26th Nishinomiya-Yukawa Memorial International Workshop "Novel Quantum States in Condensed Matter 2011 (NQS2011)"
  • Place of Presentation: Yukawa Institute for Theoretical Physics, Kyoto University(招待講演)
  • Year and Date: 2011-11-22
• [Presentation] Electronic structure and correlation effects in iron-based superconductors (2011)
  • Author(s): T.Miyake
  • Organizer: The 14th Asian Workshop on First-Principles Electronic Structure Calculations
  • Place of Presentation: Univ.Tokyo(招待講演)
  • Year and Date: 2011-11-01
• [Presentation] Alkali-metal loaded zeolites : Relativistic and correlated s electron systems (2011)
  • Author(s): Ryotaro Arita
  • Organizer: Zurich Theoretical Physics Colloquium
  • Place of Presentation: Zurich, Switzerland(招待講演)
  • Year and Date: 2011-10-31
• [Presentation] Electron-correlation physics of iron-based superconductors (2011)
  • Author(s): Masatoshi Imada
  • Organizer: International Workshop on Electronic Correlations in Models and Materials
  • Place of Presentation: Augsburg, Germany(招待講演)
  • Year and Date: 2011-09-15
• [Presentation] 第一原理計算による相関物質科学のフロンティア (2011)
  • Author(s): 三宅隆
  • Organizer: 物性研究所計算物質科学研究センター第1回シンポジウム-「京」と大型実験施設の連携に向けて-
  • Place of Presentation: 東京大学物性研究所(招待講演)
  • Year and Date: 2011-09-13
• [Presentation] Constrained RPA method for electronic states of correlated materials (2011)
  • Author(s): Takashi Miyake
  • Organizer: Joint CECAM/Psi-k Workshop on "Challenges and solutions in GW calculations for complex systems"
  • Place of Presentation: Lausanne, Switzerland(招待講演)
  • Year and Date: 2011-06-07
• [Presentation] Ab initio Derivation of Correlated Superatom Model for Potassium Loaded Zeolite A (2011)
  • Author(s): Kazuma Nakamura, Ryotaro Arita, Yoshiro Nohara, Takehito Nakano, Yasuo Nozue
  • Organizer: 16th International Symposium on Intercalation Compounds
  • Place of Presentation: Czech Eepublic(招待講演)
  • Year and Date: 2011-05-23