2001 Fiscal Year Annual Research Report

遷移金属酸化物における電荷・軌道ダイナミックスの実験的研究

Research Project

Project/Area Number	12046220
Research Institution	The University of Tokyo
Principal Investigator	内田慎一東京大学, 大学院・新領域創成科学研究科, 教授 (10114399)
Co-Investigator(Kenkyū-buntansha)	村上洋一東北大学, 大学院・理学研究所, 教授 (60190899) 松田祐司東京大学, 物性研究所, 助教授 (50199816) 藤森淳東京大学, 大学院・新領域創成科学研究科, 教授 (10209108)
Keywords	遷移金属酸化物 / スペクトロスコピー / 電荷・スピン秩序 / 軌道秩序 / 超伝導ギャップ対称性 / 角度分解光電子分光 / 共鳴X線散乱 / STM / STS
Research Abstract	遷移金属酸化物中の強相関電子系の電荷及び軌道の自由度に焦点をあて、そのダイナミックスを調べる為のスペクトロスコピー手法を開発・発展させることと、それらの自由度とスピン自由度との分離、融合により実現する新規な電子相の探求を行った。本年度の主な成果を、スペクトロスコピー別にまとめると、(1)軌道自由度がつくる秩序の形成・融解を調べる有効な手段である放射光X線を用いた共鳴X線散乱法(干渉法)の開発に成功し、軌道秩序状態の定量的解析法を発展させた。本年度は、Mn酸化物と違ってヤーン・テラー歪みが小さい、従って、軌道物理の探求により適したTi酸化物系、RTiO_3の軌道秩序が希土類元素Rの変化とともにどのように変わるかを明らかにした。 (2)磁場下での精密熱伝導度測定手法を開発し、d波やp波などの異方的超伝導ギャップ構造を決定する強力な手段であることを明らかにした。これにより非Cu酸化物超伝導体Sr_2RuO_4、重い電子系CeCoIn_5及び有機超伝導体のクーパー対の対称性に関する決定的な結果を得た。 (3)高エネルギー、高運動量分解能をもつ角度分解光電子分光法(ARPES)を高温超伝導体に適用し、これまでにない詳細な電子状態あるいはフォノンや磁気励起との結合に対する情報を得ることができるようになった。La系高温超伝導体を対象として、絶縁体母物質に微量の正孔をドープすると、運動量空間の対角線方向にフェルミ面(点)をもつ金属状態が出現し、ドーピングが進むとともに擬ギャップやd波超伝導状態にスムーズに移行する事を見出した。また、電子がフォノンと強く結合している事も明らかにした。 (4)低温STM/STS分光により、高温超伝導体のナノメートルスケールの実空間の電子情報を得ることができるようになった。高温超伝導体中に導入された磁性(Ni)、非磁性(Zn)不純物の電子状態に与える影響を解明し、ミクロに分離した相の同定や制御に不純物が有効な目印となることを示した。

Research Products

(32 results)

All Other

All Publications (32 results)

[Publications] A.Schulzgen: "Two Photon Resonant Third Harmonic Generation in La_2CuO_4"Phys. Rev. Lett.. 86. 3164-3167 (2001)
[Publications] T.Kakeshita: "Transverse Josephson Plasma Mode in T^* Cuprate Superconductors"Phys. Rev. lett.. 86. 4140-4143 (2001)
[Publications] M.Ashida: "One-dimensional cuprate as a nonlinear optical material for ultrafast all optical switching"Appi. Phys. Lett.. 78. 2831-2833 (2001)
[Publications] E.W.Hudson: "Interplay of magnetism and high-T_c superconductivity at Ni impurity atoms in Bi_2Sr_2CaCu_2O_<8+δ>"Nature. 411. 920-924 (2001)
[Publications] Y.-D.Chuang: "Doubling of the Bands in Overdoped Bi_2Sr2_C_aCu_2O_<8+δ> : Evidence for c-axis Bilayer Coupling"Phys. Rev. Lett.. 87. 117002 (2001)
[Publications] S.H.Pan: "Microscopic electronic inhomogeneity in the high-T_c superconductor Bi_2Sr_2CaCuO_<8+δ>"Phy. Rev. Lett.. 413. 282-285 (2001)
[Publications] X.J.Zhou: "Dual Nature of the Electronic Structure of the Stripe Phase"Phys. Rev. Lett.. 86. 5578-5581 (2001)
[Publications] A.Lanzara: "Ubiquitous and Almost Isotropic Coupling of Quasiparticle to Collective Excitations in High Temperature Superconductors"Nature. 412. 510-514 (2001)
[Publications] J.D.Lee: "Strong spin-fluctuation effects on the photoemission line shape in the normal state of high To cuprates"Phys. Rev. Lett.. 87. 167008-1-167008-4 (2001)
[Publications] J.D.Lee: "Efects of Acoustic Plasmons in Photoemission from Coupled Layered Systems"Phys. Rev. B. 64. 184519-1-184519-7 (2001)
[Publications] N.Harima: "Chemical potential shift in Nd_<2-x>Ce_xCuO_4 : Contrasting Behavior between the Electron-and Hole-Doped Cuprates"Phys. Rev. B. 64. 220507-1-220507-4 (2001)
[Publications] T.Koide: "Evicence for a Close Correlation between the Magnetic Moments, Lattice Distortions and Hybridization in LaMnO_3 and La_<1-x>Sr_xMnO_3+□ : Doping-Dependent Magnetic Circular X-Ray Dichroism Study"Phys. Rev. Lett.. 87. 246404-1-246404-4 (2001)
[Publications] A.Ino: "Doping Dependent Evolution of the Electronic Structure of La_<2-x>Sr_xCuO_4 in the Superconducting and Metallic Phases"Phys. Rev. B. 65. 094504-1-094504-11 (2001)
[Publications] J.D.Lee: "Photoemission in the System of Linear Chains : Application to PrBa_2Cu_3O_7 and Nd_<2-x-y>La_ySr_xCuO_4"J. Phys. Soc. Jpn.. 70. 2468-2477 (2001)
[Publications] A.Fujimori: "Electronic Structure of Mott-Hubbard Type Transition-Metal Oxides"J. Electron Spectrosc. Relat. Phenom.. 117-118. 277-287 (2001)
[Publications] A.Fujimori: "Core-Level Photoemission Measurements of the Chemical Potential Shift as a Probe of Correlated Electron Systems"J. Electron Spectrosc. Relat. Phenom.. (印刷中).
[Publications] K.Okazaki: "Temperature-dependent Electronic Structure of VO_2"J. Phys. Soc. Jpn.. (印刷中).
[Publications] K.Okazaki: "Temperature-Dependent Electronic Structure of Nd_<1-x>Sm_xNiO_3"J. Phys. Chem. Solids.
[Publications] K.Izawa: "Superconducting gap structure of spin-triplet superconductor Sr_2RuO_4..."Physical Review Letters. 86. 2653-2656 (2001)
[Publications] K.Kumagai: "Charged vortices in high-temperature superconductors probed by NMR"Physical Review B. 63. 144502-1-144502-5 (2001)
[Publications] K.Izawa: "Angular position of nodes in the superconducting gap of quasi-2D..."Physical Review Letters. 87. 057002-1-057002-4 (2001)
[Publications] K.Izawa: "Superconducting gap structure of κ-(BEDT-TTF)_2Cu(NCS)_2 probed by"Physical Review Letters. 88. 027002-1-027002-4 (2002)
[Publications] K.Kakuyanagi: "Quasiparticle excitation in and around the vortex core of underdoped"Physical Review B. 65. 060503-1-060503-4 (2002)
[Publications] T.Inami et al.: "An Inelastic X-Ray Scattering Spectrometer for Materials Science on BL11XU at SPring-8"Nuclear Instruments and Methods in Physics Research A. 467-468. 1081-1083 (2001)
[Publications] Y.Wakabayashi et al.: "Orbital and Charge Ordering in La_<1-x>Sr_<1+x>MnO_4 (0.4<x<0.5)"J. Phys. Soc. Jpn.. 70. 1194-1197 (2001)
[Publications] M.v.Zimmermann et al.: "Resonant X-ray-scattering study of Octahedral Tilt Ordering in LaMnO_3 and Pr_<1-x>Ca_xMnO_3"Phys. Rev. B. 64. 064411:1-064411:9 (2001)
[Publications] Hironori Nakao et al.: "Antiferro-Quadrupole Ordering of CeB_6 Studied by Resonant X-Ray Scattering"J. Phys. Soc. Jpn.. 70. 1857-1860 (2001)
[Publications] M.v.Zimmermann et al.: "X-ray Resonant Scattering Studies of Charge and Orbital Ordering in Pr_<1-x>Ca_xMnO_3"J. Magn. Magn. Mater.. 233. 31-37 (2001)
[Publications] Akihisa Koizumi et al.: "Study of the eg Orbitals in the Bilayer Manganite La_<2-2x>Sr_<1+2x>Mn_2O_7 by Using Magnetic Compton-Profile Measurement"Phys. Rev. Lett.. 86. 5589-5592 (2001)
[Publications] A.Fujimori: "Fermi Surface, Pseudogaps and Dynamical Stripes in La2_<2-X>Sr_xCuO_4, in Open Problems in Strongly Correlated Electron Systems"edited by J.Bonca, P.Prelovsek, A.Ramsak, S.Sarkar (Kiuwer). 119-129(11) (2001)
[Publications] Y.Matsuda: "Vortices in Unconventional Superconductors and Superfluid-Microscopic..."Springer. 18 (2001)
[Publications] 廣田和馬, 村上洋一: "丸善実験物理学講座第5巻第5章放射光-中性子-電子線による軌道秩序"丸善. 378(36) (2000)

2001 Fiscal Year Annual Research Report

遷移金属酸化物における電荷・軌道ダイナミックスの実験的研究

Principal Investigator

内田 慎一 東京大学, 大学院・新領域創成科学研究科, 教授 (10114399)

Research Products

[Publications] A.Schulzgen: "Two Photon Resonant Third Harmonic Generation in La_2CuO_4"Phys. Rev. Lett.. 86. 3164-3167 (2001)

[Publications] T.Kakeshita: "Transverse Josephson Plasma Mode in T^* Cuprate Superconductors"Phys. Rev. lett.. 86. 4140-4143 (2001)

[Publications] M.Ashida: "One-dimensional cuprate as a nonlinear optical material for ultrafast all optical switching"Appi. Phys. Lett.. 78. 2831-2833 (2001)

[Publications] E.W.Hudson: "Interplay of magnetism and high-T_c superconductivity at Ni impurity atoms in Bi_2Sr_2CaCu_2O_<8+δ>"Nature. 411. 920-924 (2001)

[Publications] Y.-D.Chuang: "Doubling of the Bands in Overdoped Bi_2Sr2_C_aCu_2O_<8+δ> : Evidence for c-axis Bilayer Coupling"Phys. Rev. Lett.. 87. 117002 (2001)

[Publications] S.H.Pan: "Microscopic electronic inhomogeneity in the high-T_c superconductor Bi_2Sr_2CaCuO_<8+δ>"Phy. Rev. Lett.. 413. 282-285 (2001)

[Publications] X.J.Zhou: "Dual Nature of the Electronic Structure of the Stripe Phase"Phys. Rev. Lett.. 86. 5578-5581 (2001)

[Publications] A.Lanzara: "Ubiquitous and Almost Isotropic Coupling of Quasiparticle to Collective Excitations in High Temperature Superconductors"Nature. 412. 510-514 (2001)

[Publications] J.D.Lee: "Strong spin-fluctuation effects on the photoemission line shape in the normal state of high To cuprates"Phys. Rev. Lett.. 87. 167008-1-167008-4 (2001)

[Publications] J.D.Lee: "Efects of Acoustic Plasmons in Photoemission from Coupled Layered Systems"Phys. Rev. B. 64. 184519-1-184519-7 (2001)

[Publications] N.Harima: "Chemical potential shift in Nd_<2-x>Ce_xCuO_4 : Contrasting Behavior between the Electron-and Hole-Doped Cuprates"Phys. Rev. B. 64. 220507-1-220507-4 (2001)

[Publications] T.Koide: "Evicence for a Close Correlation between the Magnetic Moments, Lattice Distortions and Hybridization in LaMnO_3 and La_<1-x>Sr_xMnO_3+□ : Doping-Dependent Magnetic Circular X-Ray Dichroism Study"Phys. Rev. Lett.. 87. 246404-1-246404-4 (2001)

[Publications] A.Ino: "Doping Dependent Evolution of the Electronic Structure of La_<2-x>Sr_xCuO_4 in the Superconducting and Metallic Phases"Phys. Rev. B. 65. 094504-1-094504-11 (2001)

[Publications] J.D.Lee: "Photoemission in the System of Linear Chains : Application to PrBa_2Cu_3O_7 and Nd_<2-x-y>La_ySr_xCuO_4"J. Phys. Soc. Jpn.. 70. 2468-2477 (2001)

[Publications] A.Fujimori: "Electronic Structure of Mott-Hubbard Type Transition-Metal Oxides"J. Electron Spectrosc. Relat. Phenom.. 117-118. 277-287 (2001)

[Publications] A.Fujimori: "Core-Level Photoemission Measurements of the Chemical Potential Shift as a Probe of Correlated Electron Systems"J. Electron Spectrosc. Relat. Phenom.. (印刷中).

[Publications] K.Okazaki: "Temperature-dependent Electronic Structure of VO_2"J. Phys. Soc. Jpn.. (印刷中).

[Publications] K.Okazaki: "Temperature-Dependent Electronic Structure of Nd_<1-x>Sm_xNiO_3"J. Phys. Chem. Solids.

[Publications] K.Izawa: "Superconducting gap structure of spin-triplet superconductor Sr_2RuO_4..."Physical Review Letters. 86. 2653-2656 (2001)

[Publications] K.Kumagai: "Charged vortices in high-temperature superconductors probed by NMR"Physical Review B. 63. 144502-1-144502-5 (2001)

[Publications] K.Izawa: "Angular position of nodes in the superconducting gap of quasi-2D..."Physical Review Letters. 87. 057002-1-057002-4 (2001)

[Publications] K.Izawa: "Superconducting gap structure of κ-(BEDT-TTF)_2Cu(NCS)_2 probed by"Physical Review Letters. 88. 027002-1-027002-4 (2002)

[Publications] K.Kakuyanagi: "Quasiparticle excitation in and around the vortex core of underdoped"Physical Review B. 65. 060503-1-060503-4 (2002)

[Publications] T.Inami et al.: "An Inelastic X-Ray Scattering Spectrometer for Materials Science on BL11XU at SPring-8"Nuclear Instruments and Methods in Physics Research A. 467-468. 1081-1083 (2001)

[Publications] Y.Wakabayashi et al.: "Orbital and Charge Ordering in La_<1-x>Sr_<1+x>MnO_4 (0.4<x<0.5)"J. Phys. Soc. Jpn.. 70. 1194-1197 (2001)

[Publications] M.v.Zimmermann et al.: "Resonant X-ray-scattering study of Octahedral Tilt Ordering in LaMnO_3 and Pr_<1-x>Ca_xMnO_3"Phys. Rev. B. 64. 064411:1-064411:9 (2001)

[Publications] Hironori Nakao et al.: "Antiferro-Quadrupole Ordering of CeB_6 Studied by Resonant X-Ray Scattering"J. Phys. Soc. Jpn.. 70. 1857-1860 (2001)

[Publications] M.v.Zimmermann et al.: "X-ray Resonant Scattering Studies of Charge and Orbital Ordering in Pr_<1-x>Ca_xMnO_3"J. Magn. Magn. Mater.. 233. 31-37 (2001)

[Publications] Akihisa Koizumi et al.: "Study of the eg Orbitals in the Bilayer Manganite La_<2-2x>Sr_<1+2x>Mn_2O_7 by Using Magnetic Compton-Profile Measurement"Phys. Rev. Lett.. 86. 5589-5592 (2001)

[Publications] A.Fujimori: "Fermi Surface, Pseudogaps and Dynamical Stripes in La2_<2-X>Sr_xCuO_4, in Open Problems in Strongly Correlated Electron Systems"edited by J.Bonca, P.Prelovsek, A.Ramsak, S.Sarkar (Kiuwer). 119-129(11) (2001)

[Publications] Y.Matsuda: "Vortices in Unconventional Superconductors and Superfluid-Microscopic..."Springer. 18 (2001)

[Publications] 廣田和馬, 村上洋一: "丸善実験物理学講座第5巻第5章 放射光-中性子-電子線による軌道秩序"丸善. 378(36) (2000)

内田慎一東京大学, 大学院・新領域創成科学研究科, 教授 (10114399)

[Publications] 廣田和馬, 村上洋一: "丸善実験物理学講座第5巻第5章放射光-中性子-電子線による軌道秩序"丸善. 378(36) (2000)