1996 Fiscal Year Annual Research Report

極低温超高分解能光電子分光装置の開発とフェルミ準位微細電子構造の研究

Research Project

Project/Area Number	07404017
Research Institution	Tohoku University
Principal Investigator	高橋隆東北大学, 大学院・理学研究科, 助教授 (00142919)
Co-Investigator(Kenkyū-buntansha)	田中章順東北大学, 大学院・理学研究科, 助手 (40250667)
Keywords	高分解能光電子分光 / 角度分解光電子分光 / 電子構造 / フェルミ準位 / 高温超伝導体 / 強相関 / 低次元有機伝導体 / アクチナイド
Research Abstract	本年度は、二次元電子エネルギー分析器の光電子分光装置への組み込みおよび再調整を行い最高分解能12meVを達成する事に成功した。現在、より高い分解能および信号強度を得るための調整と改良を行っている。装置の改良と並行して、角度分解光電子分光装置を用いて、興味ある様々な物質群の電子構造を非常に高いエネルギー分解能で測定、研究した。具体的には、1.銅酸化物高温超伝導体Bi_2Sr_2CaCu_2O_8の高分解能角度分解光電子分光実験を行い、その超伝導ギャップの直接観測に成功し、ギャップがdx^2-y^2の対称性を持つことを見出した。2.セリウムモノプニクタイトの低温における常磁性-反強磁性転移に伴う電子バンド構造の変化を直接観測し、転移の起源について研究した。角度分解光分子分光から、ブリルアンゾーンのΓ点にホール的フェルミ面があること、Χ点に電子的フェルミ面があることを見出し、さらにそれらの体積が磁気相転移の前後で大きく変化することを観測した。この実験結果は、p-fmixingモデルの予言と良く一致する。3.銅酸化物高温超伝導体L_<a2>CuO_4と同一の結晶構造を持ちながらCuO_2層がRuO_2層に置換されたS_<r2>RuO_4の角度分解電子分光実験を行い、銅酸化物高温超伝導体で見出されていると同様な「拡張型ファンホ-ブ特異点」が存在することを見出した。4.低次元有機金属伝導体DCNQI-Cu化合物を超高真空条件下で合成し、その金属-絶縁体転移に伴うパイエルスギャップの開閉を高分解能光電子分光で観測することに成功した。また金属相でのスペクトルの解析から、フェルミ準位近傍の電子はTomonaga-Luttinger液体を形成していることを見出した。5.ウラン化合物超伝導体UPd_2Al_3の高分解能光電子分光実験を行い、フェルミ準位近傍に2種類のU5f電子が存在し、温度によって両者の存在比が変化することを見出した。

Research Products

(26 results)

All Other

All Publications (26 results)

[Publications] T.Takahashi: "High-resolution photoemission study of deutrated dimaethyl-dicyanoquinoinedimine-Cu compound (DMe-DCNQI) _2Cu" J.Electron Spectroscopy and Related Phenomena. 78. 441-444 (1996)
[Publications] S.-H.Yang: "High-resolution photoemission study of UNi_2Al_3 and URu_2Si_2" J.Electron Spectroscopy and Related Phenomena. 78. 143-145 (1996)
[Publications] A.Ito: "Photoemission study of K-and Sc-doped C_<84>" J.Electron Spectroscopy and Related Phenomena. 78. 457-460 (1996)
[Publications] A.Tanaka: "Electron spectroscopic studies of the organic conductors DCNQI (N,N′-dicyanoquinonediimine) -Cu salts" J.Electron Spectroscopy and Related Phenomena. 78. 469-472 (1996)
[Publications] T.Yokoya: "High-resolution angle-resolved photoemission study of non-cuprate two-dimensional superconductor Sr_2RuO_4" J.Electron Spectroscopy and Related Phenomena. 78. 171-174 (1996)
[Publications] A.Chainani: "Electronic structure of Fe_3O_4 across the Verwey transition" J.Electron Spectroscopy and Related Phenomena. 78. 99-102 (1996)
[Publications] T.Takahashi: "Cooperative effects of electron correlation and charge orderring on the M-I transition in quasi 1-dimensional deutrated (DMe-DCNQI)_2Cu" Phys.Rev.B53. 1790-1794 (1996)
[Publications] T.Takahashi: "Dual character of 5f electrons in UPd_2Al_3 observed by high-resolution photoemission spectroscopy" J.Phys.Soc.Jpn.65. 156-159 (1996)
[Publications] T.Yokoya: "Extended van-Hove singularity in a non cuprate layered superconductorSr_2RuO_4" Phys.Rev.Lett.76. 3009-3012 (1996)
[Publications] H.Kumigashira: "High-energy resolution photoemission study of CeNiSi_2 and CePtSi_2" Phys.Rev.B53. 2565-2568 (1996)
[Publications] T.Yokoya: "Extended van-Hove singularity in Sr_2RuO_4 observed by angle-resolved photoemission" Physica. C263. 505-509 (1996)
[Publications] T.Yokoya: "Evidence for correlation Effects in Sr_2RuO_4 from Resonant and X-ray Photoemission Spectroacopy" Phys.Rev.B53. 8151-8154 (1996)
[Publications] H.Ding: "Electronic excitation in Bi_2Sr_2CaCu_2O_8 : Fermi surface, dispersion, and absence of bilayer splitting" Phys.Rev.Lett.176. 1533-1536 (1996)
[Publications] T.Yokoya: "High-resolution ARPES study of momentum dependence of superconducting gap in Bi_2Sr_2CaCu_2O_8" Phys.Rev.B53. 14055-14057 (1996)
[Publications] S.-H.Yang: "High-resolution photoemission study of CeRu_2 the dual character of 4f electrons" Phys.Rev.B53. R11946-R11948 (1996)
[Publications] S.-H.Yang: "High-Resolution Photoemission Study of UNi_2Al_3 and URu_2Si_2" J.Phys.Soc.Jpn.65. 2685-2689 (1996)
[Publications] H.Kumigasira: "High-resolution angle-resolved photoemission spectroscopy of CeBi" Phys.Rev.B54. 2685-2689 (1996)
[Publications] J.C.Campuzano: "Direct observation of particle-hole mixing in the superconducting state by angle-resolved photoemission" Phys.Rev.B53. R14740-R14740 (1996)
[Publications] H.Ding: "Spectroscopic evidence for a pseudogap in the normal state of underdoped high-Tc superconductors" Nature. 382. 51-54 (1996)
[Publications] T.Yokoya: "Angle-resolved photoemission study of Sr_2RuO_4" Phys.Rev.B54. 13311-13318 (1996)
[Publications] K.Ohno: "Electronic structures of C_<70> Crystalline phases" Chem.Phys.Lett.255. 367-372 (1996)
[Publications] H.Okamoto: "Electronic structure of the quasi-one-dimensional halogen-bridged Ni complexes [Ni (chxn)_2X] X_2 (X=Cl, Br) and related Ni compounds" Phys.Rev.B54. 8438-8445 (1996)
[Publications] H.Ding: "Angle-resolved photoemission spectroscopy study of the superconducting gap anisotropy in Bi_2Sr_2CaCu_2O_<8+x>" Phys.Rev.B54. R9678-R9681 (1996)
[Publications] T.Yokoya: "High-resolution temperature-dependent valence band photoemission spectroscopy of gold : Nature of electron-phonon coupling" Phys.Rev.(in press).
[Publications] H.Kumigashira: "High-resolution angle-resolved photoemission study of CeP Narrow-band formation of 4f electrons" Phys.Rev.(in press).
[Publications] H.Ding: "Evolution of the Fermi surface with carrier concentration in Bi_2Sr_2CaCu_2O_<8+δ>" Phys.Rev.Lett.(in press).

1996 Fiscal Year Annual Research Report

極低温超高分解能光電子分光装置の開発とフェルミ準位微細電子構造の研究

Principal Investigator

高橋 隆 東北大学, 大学院・理学研究科, 助教授 (00142919)

Research Products

[Publications] T.Takahashi: "High-resolution photoemission study of deutrated dimaethyl-dicyanoquinoinedimine-Cu compound (DMe-DCNQI) _2Cu" J.Electron Spectroscopy and Related Phenomena. 78. 441-444 (1996)

[Publications] S.-H.Yang: "High-resolution photoemission study of UNi_2Al_3 and URu_2Si_2" J.Electron Spectroscopy and Related Phenomena. 78. 143-145 (1996)

[Publications] A.Ito: "Photoemission study of K-and Sc-doped C_<84>" J.Electron Spectroscopy and Related Phenomena. 78. 457-460 (1996)

[Publications] A.Tanaka: "Electron spectroscopic studies of the organic conductors DCNQI (N,N′-dicyanoquinonediimine) -Cu salts" J.Electron Spectroscopy and Related Phenomena. 78. 469-472 (1996)

[Publications] T.Yokoya: "High-resolution angle-resolved photoemission study of non-cuprate two-dimensional superconductor Sr_2RuO_4" J.Electron Spectroscopy and Related Phenomena. 78. 171-174 (1996)

[Publications] A.Chainani: "Electronic structure of Fe_3O_4 across the Verwey transition" J.Electron Spectroscopy and Related Phenomena. 78. 99-102 (1996)

[Publications] T.Takahashi: "Cooperative effects of electron correlation and charge orderring on the M-I transition in quasi 1-dimensional deutrated (DMe-DCNQI)_2Cu" Phys.Rev.B53. 1790-1794 (1996)

[Publications] T.Takahashi: "Dual character of 5f electrons in UPd_2Al_3 observed by high-resolution photoemission spectroscopy" J.Phys.Soc.Jpn.65. 156-159 (1996)

[Publications] T.Yokoya: "Extended van-Hove singularity in a non cuprate layered superconductorSr_2RuO_4" Phys.Rev.Lett.76. 3009-3012 (1996)

[Publications] H.Kumigashira: "High-energy resolution photoemission study of CeNiSi_2 and CePtSi_2" Phys.Rev.B53. 2565-2568 (1996)

[Publications] T.Yokoya: "Extended van-Hove singularity in Sr_2RuO_4 observed by angle-resolved photoemission" Physica. C263. 505-509 (1996)

[Publications] T.Yokoya: "Evidence for correlation Effects in Sr_2RuO_4 from Resonant and X-ray Photoemission Spectroacopy" Phys.Rev.B53. 8151-8154 (1996)

[Publications] H.Ding: "Electronic excitation in Bi_2Sr_2CaCu_2O_8 : Fermi surface, dispersion, and absence of bilayer splitting" Phys.Rev.Lett.176. 1533-1536 (1996)

[Publications] T.Yokoya: "High-resolution ARPES study of momentum dependence of superconducting gap in Bi_2Sr_2CaCu_2O_8" Phys.Rev.B53. 14055-14057 (1996)

[Publications] S.-H.Yang: "High-resolution photoemission study of CeRu_2 the dual character of 4f electrons" Phys.Rev.B53. R11946-R11948 (1996)

[Publications] S.-H.Yang: "High-Resolution Photoemission Study of UNi_2Al_3 and URu_2Si_2" J.Phys.Soc.Jpn.65. 2685-2689 (1996)

[Publications] H.Kumigasira: "High-resolution angle-resolved photoemission spectroscopy of CeBi" Phys.Rev.B54. 2685-2689 (1996)

[Publications] J.C.Campuzano: "Direct observation of particle-hole mixing in the superconducting state by angle-resolved photoemission" Phys.Rev.B53. R14740-R14740 (1996)

[Publications] H.Ding: "Spectroscopic evidence for a pseudogap in the normal state of underdoped high-Tc superconductors" Nature. 382. 51-54 (1996)

[Publications] T.Yokoya: "Angle-resolved photoemission study of Sr_2RuO_4" Phys.Rev.B54. 13311-13318 (1996)

[Publications] K.Ohno: "Electronic structures of C_<70> Crystalline phases" Chem.Phys.Lett.255. 367-372 (1996)

[Publications] H.Okamoto: "Electronic structure of the quasi-one-dimensional halogen-bridged Ni complexes [Ni (chxn)_2X] X_2 (X=Cl, Br) and related Ni compounds" Phys.Rev.B54. 8438-8445 (1996)

[Publications] H.Ding: "Angle-resolved photoemission spectroscopy study of the superconducting gap anisotropy in Bi_2Sr_2CaCu_2O_<8+x>" Phys.Rev.B54. R9678-R9681 (1996)

[Publications] T.Yokoya: "High-resolution temperature-dependent valence band photoemission spectroscopy of gold : Nature of electron-phonon coupling" Phys.Rev.(in press).

[Publications] H.Kumigashira: "High-resolution angle-resolved photoemission study of CeP Narrow-band formation of 4f electrons" Phys.Rev.(in press).

[Publications] H.Ding: "Evolution of the Fermi surface with carrier concentration in Bi_2Sr_2CaCu_2O_<8+δ>" Phys.Rev.Lett.(in press).

高橋隆東北大学, 大学院・理学研究科, 助教授 (00142919)