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1992 Fiscal Year Annual Research Report

有機導体における強い相関をもつ低次元電子系の研究

Research Project

Project/Area Number 03302017
Research InstitutionUniversity of Tokyo

Principal Investigator

鹿児島 誠一  東京大学, 教養学部 教授 (30114432)

Co-Investigator(Kenkyū-buntansha) 大嶋 孝吉  岡山大学, 理学部, 教授 (10114414)
高田 慧  筑波大学, 物理学系, 教授 (10015779)
石黒 武彦  京都大学, 理学部, 教授 (50202982)
梶田 晃示  東邦大学, 理学部, 教授 (50011739)
豊田 直樹  東北大学, 金属材料研究所, 助教授 (50124607)
Keywords有機導体 / 電子相関 / 低次元電子 / 電気伝導 / 電荷密度 / スピン密度 / 磁気抵抗 / 価数揺動
Research Abstract

この研究の目的は,低次元電子系をもつ有機導体において,電子間クーロン相関が低次元電子の振る舞いに与える影響を明らかにするこである。今年度は,TMTSF系物質,BEDT-TTF系物質,およびDCNQI-Cu系物質について以下のような著しい成果を得た。
まずTMTSF系物質では,低次元性と電子間相関とによって起こる磁場誘起スピン密度波状態とこれに関連する電子物性の理解を進めた。数種の物質の比較によって,CIO4塩の高磁場極限相が量子数ゼロのスピン密度波状態であると理釈でき,負イオンの作るポテンシャルがこの相の現れかたや磁気抵抗の早い振動と関係しているこを示した。
BEDT-TTF系物質でも,低温でフェルミ面の不安定性に関係したどのような磁気的状態があるかを調ベた。K塩,NH4塩の他に,Rb塩についても現象を明らかにし,Rb塩はK塩と本質的には同様であることを示した。K塩の「反強磁性」と孝えられる状態の磁気異方性,フェルミ面形状の圧力変化,K塩の「反強磁性」状態の圧力変化などを調べた。K塩の「反強磁性」状態は,8K以下の低温,23T以下の弱磁場,5Kbar以下の低圧領域で存在することを明らかにした。
DCNQI塩では,DCNQI-Cu塩の絶縁体状態での反強磁性構造を,磁性および構造の研究によって明らかにした,また,水素を一部重水素に置換した物質では常圧で金属-絶縁体-金属リエントランス転移が起こることを発見し,リエントランスの詳細を解体した。この系統の物質の金属-絶縁体転移の本質は,DCNQIのパイ電子バンドのフェルミ面不安定性に関係するバイエルス転移と,銅のd電子のバンドについてのモット転移であることを示した。この系では,低次元性,電子相関,電子格子相互作用,および圧力による弱い3次元性の介入のすべてが本質的な役割を哀じていると言える。

  • Research Products

    (39 results)

All Other

All Publications (39 results)

  • [Publications] S.Kagoshima,et at: "Magnetotransprt Studies of the Topology of Fermi Surface of the Quasi Two-Dimensional Organic Superconductor(BEDT-TTF)_2(NH_4)Hg-(SCN)_4,the Isostrctual Metal (BEDT-TTF)_2KHg(SCN)_4,and the Quasi" JJAP Serise 7,Mechanisms of Superconductivity. 381-389 (1992)

  • [Publications] T.Nakamura, et al: "FERMI SURFACE TOPOLOGY AND ELECTRONIC STRUCTURES OF TWO-DIMENSIONAL ORGANIC CONDUCTORS BASED ON BEDT-TTF AND MDT-TTF" Phosphorus,Sulfur,and Silicon. 67. 377-382 (1992)

  • [Publications] T.Osada,S.Kagoshima,and N.Miura: "Resonance effect in magnetotransport anisotropy of quasi--one-dimensiona conductors" Physical Review B. 46. 1812-1815 (1992)

  • [Publications] T.Osada, S.Kagoshima,and N.Miura: "FIELD-INDUCED SPIN-DENSITY-WAVE INSTABILETY OF THE ANISOTROPIC TWO-DI,ENSIONAL ELECTRON SYSTEM INDER LATRERAL SIPERLATTICE POTENTEAL" Phtsical Review Letters. 69. 1117-1120 (1992)

  • [Publications] T.Kouno, T.Osada, M.Hasumi,and S.Kagashima: "A NOVEL ELECTRONIC STATE IN(BEDT-TTF)_2XHg(SCN)_4;X=K,NH_4" Synthetic Metals,to be published.

  • [Publications] T.Sasaki, N.toyota: "Magnetic Phase Diagran of the Organic Conductor α-(BEDT-TTG)_2KHg(SCN)_4" Solid State Commun.82. 447-451 (1992)

  • [Publications] 徳本圓,A.Swanson,J.Brooks C.Agosta,S.Hananhs,木下信盛京安西弘行、田村雅史、田島裕之 黒田晴雄、鵜川彰人、薬師久弥: "Fermi Surface Strface of Orgapic Netals(BEDT-TTF)_2X" Mat.Res.Soc.Symp.Proc.Electrlcal.Optical and Magnetic Properties of Orgnic Solid State Materials.Eds.L.Y.Chiang,A.F.Garito and D.J.Sandman. 247. 515-522 (1992)

  • [Publications] N.A.Fortune,村田恵三、池田久美、高橋梨宏: "Competitlon between Superconductivitu and a New 2OK Phase in β-(BEDT-TTF)_2I_3" Phys.Rev.Letters. 68. 2933-2936 (1992)

  • [Publications] J.Brooks,C.Agosta,S.Klepper 徳本圓、木下信盛、安西弘行 宇治伸也、青木晴善、A.Perel G.Athas,D.Howe: "Novel Interplay of Fermi-Surface Bahavior and Magnetism in a Low-Dimensionl Organic Conductor" Phys. Rev. Letters. 69. 156-159 (1992)

  • [Publications] 木下信盛、田中康資、徳田 圓 松宮茂樹: "Superconductivity and Electron Spin tesonance in Cs-Doped C_<60>" Solid State Commun.83. 883-886 (1992)

  • [Publications] 関根 久、前田 弘、小菅通雄 田中吉秋、徳本 圓: "Magnetic Behavior and Structure of the Halogen-Doped Fullerene C_<60>" J.AppL.Phys. 72. 5448-5450 (1992)

  • [Publications] 石橋章司、寺田教男、徳本 圓 木下信盛、伊原英雄: "Positron States in C_<60> and Pottasium-Doped C_<60> Crystals" J. Phys.:Condensed Matter. 4. L169-L177 (1992)

  • [Publications] 石橋章司、徳本 圓、木下信盛 寺田教男、伊原英雄: "Positron States in β-(BEDT-TTF)_2I_3" Solid Stste Commun.85. 397-399 (1993)

  • [Publications] T.Ojiro, et al.: "An Anomalous Magnetoresistance in α-(BEDT-TTF)_2I_3 under High Pressure:A Possible New Phase" Physica B,to be published.

  • [Publications] M.Lang, N.Toyota T, Sasaki, H.Sato: "Matnetic penitration depth of κ-(BEDT-TTF)_2Cu(N(CN)_2)Bス, determined from the rdsersible nagnetization" Phys. Rev.B. 46. 5822-5825 (1992)

  • [Publications] M.Lang, N. Toyora, T. Sasakニ, H. Sato: "Magnetic penetration and of κ-(BEDT-TTF)_2Cu(NCS)_2: Strong evidence for cnoventionalCooper pairing" Phys. Rev. Lett.69. 1443-1447 (1992)

  • [Publications] Y.Nishio, et al: "Thermal and Magnetic Properties in Organic Metals (DMe-DCNQI)_2Cu, (DMeO-DCNQI)_2Cu and (DME_<1-x>MeBr_x-DCNQI)_2Cu" Solid State Commun.81. 472- (1992)

  • [Publications] T.Mishima, et al: "The Metal-Insulator Transiton in the Organic Conductor α-(BEDT-TTF)_2I_3---Viewed by Microwave" Synthetic Metals.

  • [Publications] H. Fujii, et al: "Sudden Disappearance of the Superconctivety of κ-(BEDT-TTF)_2Cu(SCN)_2" Synthetic Metals,.

  • [Publications] T.Ojiro, er al.: "A New Magneto-pressure Phase in α-(BDDT-TTF)_2I_3" Synthetic MetalS,.

  • [Publications] T.Takahashi, et al.: "Magnetism of DCNQI-Cu Salts" Synth. Met.

  • [Publications] K.Kanoda, et al.: "Magnetic Penetration Depth of the κ-Phase Family of Organic Superconductors" Synth. Met.

  • [Publications] K. Kanoda, et al.: "Upper Critical Field and NMR Relaxation of an Organic Superconductor, κ-(MDT-TTF)_2Aiu_2" Synth. Met.

  • [Publications] T. Takahashi, et al.: "Pressure Dependence of the SDW Transition in(MDT-TTF)_2-Au(CN)_2" Synth. Met.

  • [Publications] T.Takahashi, et al.: " _1H-NMR relaxation Anomaly at the Metal-Metal transition in the Slowly-Cooled (BEDT-TTF)_2C10_4(C_2H_3CL_3)_<0.5>" Synth.Met.

  • [Publications] T.Takahasi, et al.: " _1H-NMR Studies of the Low Temperature Phase of α-(BEDT-TTF)_2KHg(SCN)4"

  • [Publications] K.Kanoda, et al.: "Observation of de Haas-van Alphen Oscillations in (DMET)_2AuBr_2" Synth. Met.

  • [Publications] S.Kagoshima, et al: "Charge and Spin States of DCNQI-Cu Salts" Synth. Met.

  • [Publications] S.Murata, et al.: "Evidence for a 20K Transition in β-(BEDT-TTF)_2I_3" Xyznth. Met.

  • [Publications] T.Nakamura, et al.: "Transport Prooperties and Electronic Structure of the Novel Organic Superconductor κ-(BEDT-TTF)_2Cu(CN)[N(CN)_2](Tc=11.2K)" Synth.Met.

  • [Publications] H.Ito, et al.: "On superconductivity of the organic conductor α-(BEDT-TTF)_2KHg(SCN)_4" Solid State Commun.

  • [Publications] H.Ito, et al.: "Temperature Dependence of electrical conductivity of α-(BEDT-TTF)_2KHg(SCN)_4 below 1K:Possible electronic Phase change at 200mk" Xynthetic Metals.

  • [Publications] H.Ito, et al.: "Resistive Transition of κ-(BEDT-TTF)_2Cu[N(CN)_2]Br super-conductor under magnetic field" Synthetic Metals.

  • [Publications] K.Oshima, et al.: "XANES and EXAFS Study in(R_1R_2-DCNQI)_2Cu" JPN.J.Appl.Phys.

  • [Publications] K.Oshima, et al.: "The Field Induced Transitions in a Novel Organic System,(DMET-TSeF)_2AuI_2" Synthetic Metals.

  • [Publications] K. Oshima, et al.: "XANES Study and Valence States in)R_1_R-DCNQI)_2Cu" Synthetic Metals.

  • [Publications] S.Takada: "Nonlocal Unitary Trancsormation and String Order in S_21/2Heisenbery chain with Bond Alternation" J.Phys. Soc. JPN.61. 428-432 (1992)

  • [Publications] H.Shimahara,and S. Takada: "Fragility of the Antiferromagnetic Long-Rarge-Order and Spin Correlation in The Two Dimensional T-J Model" J. Phys. Soc. JPN.61. 989-997 (1992)

  • [Publications] T.Ishiguro and Y.Nogami: "Frontiers in Solid State Sciences. ed.by L.C.Gupta and M.S.Multani to be published." World Scientific,

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Published: 1994-03-23   Modified: 2016-04-21  

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