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2008 Fiscal Year Annual Research Report

分子性低次元導体の光誘起相転移動力学の理論

Research Project

Project/Area Number 19540381
Research InstitutionInstitute for Molecular Science

Principal Investigator

米満 賢治  Institute for Molecular Science, 理論・計算分子化学研究領域, 准教授 (60270823)

Keywords中性イオン性転移 / 反強誘電転移 / 量子相転移 / コヒーレント振動 / 逆スピンパイエルス転移 / 光誘起絶縁体金属転移 / 電子格子相互作用 / 緩和過程
Research Abstract

交互積層型電荷移動錯体のDMTTF-QBr_nCl_<4-n>は常誘電中性相-反強誘電イオン性相の転移温度がnの増大とともに下がり、n=2で絶対零度付近となる。中性相では量子常誘電相に特有な誘電率の温度変化を示すことが知られている。この量子相転移付近の中性相で光照射すると、電荷移動量に敏感な反射率成分が大振幅でコヒーレント振動することが最近報告された。そのメカニズムを、サイトあたり3状態をとるBlume-Emery-Griffiths模型に量子トンネル項を加えて解析した。多体波動関数に対して時間依存シュレディンガー方程式を解いたところ、量子臨界点近傍で振動の振幅が増大することがわかった。しかしダイナミクスに非線型性は現れず、相転移を誘起しない実験事実と矛盾しない。
光誘起相転移では分子密度に比べてずっと低い密度の光子で、電子状態が巨視的に変わるので、光スイッチなどへの応用が期待されている。そのためには絶縁体を光照射して生成した金属状態が高速に緩和することが期待され、強相関電子系では実現している。そこで格子振動の重要性を考え、異なる型の電子格子相互作用を持つ1次元1/2-filled Hubbard模型で、光励起された電子系から格子系へのエネルギー移動率を厳密な多電子波動関数により調べた。通常の電子格子相互作用は電子状態の対称性に関わる点では重要だが、エネルギー移動率は対称性によって大きく異なる。電子間斥力を変調する型の相互作用は平衡状態の性質には効かないが、対称性によらずエネルギー移動に大きく関与する。

  • Research Products

    (26 results)

All 2009 2008

All Journal Article (7 results) (of which Peer Reviewed: 7 results) Presentation (18 results) Book (1 results)

  • [Journal Article] Charge Order with Structural Distortion in Organic Conductors : Comparison between θ-(ET)_2RbZn(SCN)_4 and α-(ET)_2I_32008

    • Author(s)
      Y. Tanaka, K. Yonemitsu
    • Journal Title

      J. Phys. Soc. Jpn. 77

      Pages: 034708

    • Peer Reviewed
  • [Journal Article] Polaronic States with Spin-Charge-Coupled Excitation in a One-Dimensional Dimerized Mott Insulator K-TCNQ2008

    • Author(s)
      N. Maeshima, K. Yonemitsu
    • Journal Title

      J. Phys. Soc. Jpn. 77

      Pages: 074713

    • Peer Reviewed
  • [Journal Article] Theory of Photoinduced Phase Transitions in Itinerant Electron Systems2008

    • Author(s)
      K. Yonemitsu, K. Nasu
    • Journal Title

      Phys. Rep. 465

      Pages: 1-60

    • Peer Reviewed
  • [Journal Article] Photoinduced Change in the Charge Ordering Pattern in the Quarter-Filled Organic Conductor (EDO-TTF)_2PF_6 with a Strong Electron-Phonon Interaction2008

    • Author(s)
      K. Onda, S. Ogihara, K. Yonemitsu, N. Maeshima, T. Ishikawa, Y. Okimoto, X. Shao, Y. Nakano, H. Yamochi, G. Saito, S. Koshihara
    • Journal Title

      Phys. Rev. Lett 101

      Pages: 067403

    • Peer Reviewed
  • [Journal Article] Spin and Charge Fluctuations and Lattice Effects on Charge Ordering in α-(BEDT-TTF)_2I_32008

    • Author(s)
      S. Miyashita, K. Yonemitsu
    • Journal Title

      J. Phys. Soc. Jpn. 77

      Pages: 094712

    • Peer Reviewed
  • [Journal Article] Enhanced Coherent Dynamics near a Transition between Neutral Quantum-Paraelectric and Ionic Ferroelectric Phases in the Quantum Blume-Emery-Griffiths Model2008

    • Author(s)
      K. Yonemitsu
    • Journal Title

      Phys. Rev. B 78

      Pages: 205102

    • Peer Reviewed
  • [Journal Article] Modified Barrett Formula near the Neutral-Ionic Quantum Phase Transition2008

    • Author(s)
      Y. Yamashita, K. Yonemitsu
    • Journal Title

      J. Phys. : Conf. Ser. 132

      Pages: 012019

    • Peer Reviewed
  • [Presentation] 金属モット絶縁体界面での整流作用の抑制:非平衡グリーン関数によるアプローチ2009

    • Author(s)
      米満賢治
    • Organizer
      日本物理学会第64回年次大会
    • Place of Presentation
      東京
    • Year and Date
      2009-03-30
  • [Presentation] 2軌道ハバード鎖における光誘起ダイナミクス2009

    • Author(s)
      前島展也、日野健一、米満賢治
    • Organizer
      日本物理学会第64回年次大会
    • Place of Presentation
      東京
    • Year and Date
      2009-03-28
  • [Presentation] 2次元有機導体における光誘起ダイナミクス2009

    • Author(s)
      宮下哲、田中康寛、米満賢治
    • Organizer
      日本物理学会第64回年次大会
    • Place of Presentation
      東京
    • Year and Date
      2009-03-28
  • [Presentation] 金属絶縁体界面を通した輸送の特性:電子相関と界面障壁2008

    • Author(s)
      米満賢治
    • Organizer
      第2回研究会「金属錯体の固体物性科学最前線-錯体化学と固体物性物理の新奇融合領域創成をめざして-」
    • Place of Presentation
      仙台
    • Year and Date
      2008-12-21
  • [Presentation] Photoinduced phase transitions and dynamics in organic conductors2008

    • Author(s)
      K. Yonemitsu
    • Organizer
      SOKENDAI Asian Winter School, "Molecular Sciences on Different Space-Time Scales"
    • Place of Presentation
      Okazaki (Japan)
    • Year and Date
      2008-12-10
  • [Presentation] Wave-particle dual nature and phase diagram of organic conductors2008

    • Author(s)
      K. Yonemitsu
    • Organizer
      SOKENDAI Asian Winter School, "Molecular Sciences on Different Space-Time Scales"
    • Place of Presentation
      Okazaki (Japan)
    • Year and Date
      2008-12-10
  • [Presentation] Photogenerated polaronic state in a one-dimensional dimerized Mott insulator K-TCNO2008

    • Author(s)
      N. Maeshima, K. Yonemitsu, K. Hino
    • Organizer
      Yamada Conference LXIII, 3rd International Conference on "Photoinduced Phase Transitions and Cooperative Phenomena"
    • Place of Presentation
      Osaka (Japan)
    • Year and Date
      2008-11-13
  • [Presentation] Effects of spin fluctuations, charge fluctuations and lattice distortions on charge orders in θ- and α-type BEDT-TTF salts2008

    • Author(s)
      S. Miyashita, K. Yonemitsu
    • Organizer
      Yamada Conference LXIII, 3rd International Conference on "Photoinduced Phase Transitions and Cooperative Phenomena"
    • Place of Presentation
      Osaka (Japan)
    • Year and Date
      2008-11-13
  • [Presentation] Photoinduced melting of charge order in quasi-two-dimensional organic conductors2008

    • Author(s)
      Y. Tanaka, K. Yonemitsu
    • Organizer
      Yamada Conference LXIII, 3rd International Conference on "Photoinduced Phase Transitions and Cooperative Phenomena"
    • Place of Presentation
      Osaka (Japan)
    • Year and Date
      2008-11-13
  • [Presentation] Photoinduced Melting and Charge Order in Quarter-Filled Organic Conductors : Itinerant Electron Systems with Competing Interactions2008

    • Author(s)
      K. Yonemitsu, N. Maeshima, Y. Tanaka, S. Miyashita
    • Organizer
      Yamada Conference LXIII, 3rd International Conference on "Photoinduced Phase Transitions and Cooperative Phenomena"
    • Place of Presentation
      Osaka (Japan)
    • Year and Date
      2008-11-11
  • [Presentation] 軌道縮退ハバード模型における光誘起ダイナミクス2008

    • Author(s)
      前島展也、米満賢治、日野健一
    • Organizer
      日本物理学会2008年秋季大会
    • Place of Presentation
      岩手
    • Year and Date
      2008-09-22
  • [Presentation] 擬二次元有機導体における電荷秩序の光誘起融解2008

    • Author(s)
      田中康寛、米満賢治
    • Organizer
      日本物理学会2008年秋季大会
    • Place of Presentation
      岩手
    • Year and Date
      2008-09-21
  • [Presentation] Photoinduced Charge Dynamics in Organic Conductors and Coherent Neutral-Ionic/Polarization Dynamics in Quantum Paraelectrics2008

    • Author(s)
      K. Yonemitsu, N. Maeshima, Y. Yamashita
    • Organizer
      International Symposium on Molecular Conductors 2008 "Novel Functions of Molecular Conductors under Extreme Conditions"
    • Place of Presentation
      Okazaki (Japan)
    • Year and Date
      2008-07-25
  • [Presentation] Suppression of Rectification at Interfaces between Metals and Organic Mott Insulators2008

    • Author(s)
      K. Yonemitsu, N. Maeshima, T. Hasegawa
    • Organizer
      International Symposium on Molecular Materials Chemistry, Solid State Physics, Theory, Nanotechnology From Molecule to Molecular Device (MOLMAT2008)
    • Place of Presentation
      Toulouse (France)
    • Year and Date
      2008-07-08
  • [Presentation] Energy transfer to phonons after photoexcitation in one-dimensional correlated electron-phonon systems2008

    • Author(s)
      K. Yonemitsu, N. Maeshima
    • Organizer
      2008 International Conference on Excitonic Processes in Condensed Matter (EXCON'08)
    • Place of Presentation
      Kyoto (Japan)
    • Year and Date
      2008-06-26
  • [Presentation] Photoinduced Charge Order with Delocalized Electrons in Quarter-Filled Organic Conductors2008

    • Author(s)
      K. Yonemitsu, N. Maeshima
    • Organizer
      1st International Conference of The Grand Challenge to Next-Generation Integrated Nanoscience
    • Place of Presentation
      Tokyo (Japan)
    • Year and Date
      2008-06-04
  • [Presentation] Charge Order and Lattice Distortion in Quasi-Two-Dimensional Organic Conductors2008

    • Author(s)
      Y. Tanaka, K. Yonemitsu
    • Organizer
      1st International Conference of The Grand Challenge to Next-Generation Integrated Nanoscience
    • Place of Presentation
      Tokyo (Japan)
    • Year and Date
      2008-06-04
  • [Presentation] Strong-Coupling Analysis of Effects of Electron-Phonon Couplings on Charge Orders in θ- and α-Type BEDT-TTF Salts2008

    • Author(s)
      S. Miyashita, K. Yonemitsu
    • Organizer
      1st International Conference of the Grand Challenge to Next-Generation Integrated Nanoscience
    • Place of Presentation
      Tokyo (Japan)
    • Year and Date
      2008-06-04
  • [Book] 光誘起相転移の理論-コヒーレント振動と過渡状態-レーザー研究(The Review of Laser Engineering) 36, No. 6, 343-3482008

    • Author(s)
      米満賢治
    • Total Pages
      6
    • Publisher
      レーザー学会

URL: 

Published: 2010-06-11   Modified: 2016-04-21  

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