Synthesis and phase control of fullerene based superstructured materials

• Project/Area Number: 15340106
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Condensed matter physics II
• Research Institution: Tohoku University
• Principal Investigator: TAGUCHI Yasujiro Tohoku University, Institute for Materials Research, associate professor, 金属材料研究所, 助教授 (70301132)
• Co-Investigator(Kenkyū-buntansha): IWASA Yoshihiro Tohoku University, Institute for Materials Research, professor, 金属材料研究所, 教授 (20184864)
• Project Period (FY): 2003 – 2004
• Project Status: Completed (Fiscal Year 2004)
• Budget Amount: ¥14,400,000 (Direct Cost: ¥14,400,000); Fiscal Year 2004: ¥4,600,000 (Direct Cost: ¥4,600,000); Fiscal Year 2003: ¥9,800,000 (Direct Cost: ¥9,800,000)
• Keywords: fullerene / alkali metal intercalation / insulator-superconductor transition / solid solution / electronic specific heat / density of states / Jahn-Teller interaction / orbital degeneracy / ヤン・テラー相互作用 / 金属内包フラーレン / 薄膜 / 電界効果トランジスター / 光吸収スペクトル / ホッピング伝導 / バンド伝導

Research Abstract

In this fiscal year, we have tried to reveal universality and unique points in fullerene based compounds, dealing with layered nitride superconductors that also exhibit band insulator to superconductor transition similarly to the case of alkali metal intercalated fullerides. We have succeeded in preparing a series of samples with continuously changed Li-content (x<0.12), and have confirmed that these are of single phase by using synchrotron X-ray diffraction technique at BL2B-02, SPring 8. This fact makes striking contrast with the case of fullerides where only line phases exist and the intermediate phases can not be obtained, clearly indicating the anomalous solid state chemistry of fullerene compounds. Also, we have performed the specific heat measurements of layered nitride superconductors in magnetic fields, and have found that the normal-state Sommerfeld constant γ is very small (=1.0 mJ/mol K^2). We can obtain very small electron-phonon coupling constant λ(=0.22) by using this value and the density of states at the Fermi level predicted by several band calculations. This fact is in accord with the relatively narrow phonon lines observed in Raman scattering spectra. This fact also makes striking contrast with the fullerides where superconductivity is mediated by high frequency phonon with intermediate electron-phonon coupling strength, indicating the importance of Jahn-Teller interaction where the fullerene molecules show deformation. It is theoretically pointed out that Jahn-Teller interaction that couples with the degenerate LUMO orbitals is important in fullerides, and our result is consistent with this.

Research Products

• [Journal Article] Determination of the orbital moment and crystal-field splitting in LaTiO3 (2005)
  • Author(s): H.W.Haverkort et al.
  • Journal Title: Phys.Rev.Lett. 94 Pages: 56401-56401
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Determination of the orbital moment and crystal-field splitting in LaTiO3 (2005)
  • Author(s): H.W.Haverkort, Z.Hu, A.Tanaka, G.Ghiringhelli, M.Cwik, T.Lorenz, C.Schussler-Langeheine, S.V.Streltsov, A.S.Mylnikova, V.I.Anisimov, C.de Nadai, N.B.Brookes, H.H.Hsieh, H.J.Lin, C.T.Chen, T.Mizokawa, Y.Taguchi, Y.Tokura, D.I.Khomskii, L.H.Tjeng
  • Journal Title: Physical Review Letters Vol.94
  • NAID: 120000879716
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Charge dynamics in underdoped Nd_<2-x>Ce_xCuO_4 : Pseudogap and related phenomena (2004)
  • Author(s): Y.Onose et al.
  • Journal Title: Phys.Rev.B 69 Pages: 24504-24504
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Fully gapped single-particle excitations in lightly doped cuprates (2004)
  • Author(s): K.M.Shen et al.
  • Journal Title: Phys.Rev.B 69 Pages: 54503-54503
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Chemical control of spin chirality in (Nd_<1-x>Dy_x)_2Mo_2O_7 (2004)
  • Author(s): S.Iguchi et al.
  • Journal Title: Phys.Rev.B 69 Pages: 220401-220401
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Specific-heat study of the spin-structural change in pyrochlore Nd_2Mo_2O_7 (2004)
  • Author(s): Y.Onose et al.
  • Journal Title: Phys.Rev.B 70 Pages: 60401-60401
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Linear and nonlinear optical properties of one-dimensional Mott insulators consisting of Ni-halogen chain and CuO chain compounds (2004)
  • Author(s): M.Ono et al.
  • Journal Title: Phys.Rev.B 70 Pages: 85101-85101
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Raman study of the metal-insulator transition in pyrochlore Mo oxides (2004)
  • Author(s): K.Taniguchi et al.
  • Journal Title: Phys.Rev.B 70 Pages: 100401-100401
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] High-pressure study of layered nitride superconductors (2004)
  • Author(s): Y.Taguchi et al.
  • Journal Title: Phys.Rev.B 70 Pages: 104506-104506
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Orbital ordering near a Mott transition : Resonant x-ray scattering study of the perovskite Ti oxides RTiO_3 and LaTiO_<3.02> (R=Gd, Sm, Nd and La) (2004)
  • Author(s): M.Kubota et al.
  • Journal Title: Phys.Rev.B 70 Pages: 245125-245125
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Charge dynamics near the electron-correlation induced metal-insulator transition in pyrochlore-type molybdates (2004)
  • Author(s): I.Kezsmarki et al.
  • Journal Title: Phys.Rev.Lett 93 Pages: 266401-266401
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] The spin chirality induced anomalous Hall effect in pyrochlore ferromagnets (2004)
  • Author(s): Y.Taguchi et al.
  • Journal Title: J.Phys.Cond.Matt. 16
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Charge dynamics in underdoped Nd_<2-x>Ce_XCuO_4 : Pseudogap and related phenomena (2004)
  • Author(s): Y.Onose, Y.Taguchi, K.Ishizaka, Y.Tokura
  • Journal Title: Physical Review B Vol.69
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Fully gapped single-particle excitations in lightly doped cuprates (2004)
  • Author(s): K.M.Shen, T.Yoshida, D H.Lu, F.Ronning, N.P.Armitage, W.S.Lee, X.J.Zhou, A.Damascelli, D.L.Feng, N.J.C.Ingle, H.Eisaki, Y.Kohsaka, H.Takagi, T.Kakeshita, S.Uchida, P.K.Mang, M.Greven, Y.Onose, Y.Taguchi, Y.Tokura, S.Komiya, Y.Ando, M.Azuma, M.Takano, A.Fujimori, Z.-X.Shen
  • Journal Title: Physcal Review B Vol.69
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Chemical control of spin chirality in (Nd<1-x>Dy_x)_2Mo_2O_7 (2004)
  • Author(s): S.Iguchi, D.Hashimoto, Y.Taguchi, Y.Tokura
  • Journal Title: Physical Review B Vol.69
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Specific-heat study of the spin-structural change in pyrochlore Nd_2Mo_2O_7 (2004)
  • Author(s): Y.Onose, Y.Taguchi, T.Ito, Y.Tokura
  • Journal Title: Physical Review B Vol.70
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Linear and nonlinear optical properties of one-dimensional Mott insulators consisting of Ni-halogen chain and CuO chain compounds (2004)
  • Author(s): M.Ono, K.Miura, A.Maeda, H.Matsuzaki, H.Kishida, Y.Taguchi, Y.Tokura, M.Yamashita, H.Okamoto
  • Journal Title: Physical Review B Vol.70
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Raman study of the metal-insulator transition in pyrochlore Mo oxides (2004)
  • Author(s): K.Taniguchi, T.Katsufuji, S.Iguchi, Y.Taguchi, H.Takagi, Y.Tokura
  • Journal Title: Physical Review B Vol.70
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] High-pressure study of layered nitride superconductors (2004)
  • Author(s): Y.Taguchi, M.Hisakabe, Y.Ohishi, S.Yamanaka, Y.Iwasa
  • Journal Title: Physical Review B Vol.70
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Orbital ordering near a Mott transition : Resonant x-ray scattering study of the perovskite Ti oxides RTiO_3 and LaTiO_<3.02> (R=Gd, Sm, Nd and La (2004)
  • Author(s): M.Kubota, H.Nakao, Y.Murakami, Y.Taguchi, M.Iwama, Y.Tokura
  • Journal Title: Physical Review B Vol.70
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Charge dynamics near the electron-correlation induced metal-insulator transition in pyrochlore-type molybdates (2004)
  • Author(s): I.Kezsmarki, N.Hanasaki, D.Hashimoto, S.Iguchi, Y.Taguchi, S.Miyasaka, Y.Tokura
  • Journal Title: Physical Review Letters Vol.93
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Charge dynamics in underdoped Nd_<2-x>Ce_xCuO_4:Pseudogap and related phenomena (2004)
  • Author(s): Y.Onose et al.
  • Journal Title: Phys.Rev.B 69 Pages: 24504-24504
• [Journal Article] Charge dynamics near the electron-correlation induced metal-insulator transition in pyrochlore-type molybdates (2004)
  • Author(s): I.Kezsmarki et al.
  • Journal Title: Phys.Rev.Lett. 93 Pages: 266401-266401
• [Publications] K.Ishizaka et al.: "Charge ordering and charge dynamics in Nd_<2-X>Sr_XNiO_4"Physical Review B. 67. 184418-1-184418-8 (2003)
• [Publications] Y.Taguchi et al.: "Magnetic field induced sign reversal of the anomalous Hall effect in a pyrochlore ferromagnet Nd2Mo2O7 : Evidence for a spin chirality mechanism"Physical Review Letters. 90. 257202-1-257202-4 (2003)
• [Publications] S.Kobayashi et al.: "Conductivity and Field Effect Transistor of La_2@C_<80> Metallofullerene"Journal of American Chemical Society. 125. 8116-8117 (2003)
• [Publications] T.Higuchi et al.: "On-site Coulomb energy versus crystal-field splitting for the insulator-metal transition in La_<1-X>Sr_XTiO_3"Physical Review B. 68. 104420-1-104420-5 (2003)
• [Publications] Y.Onose et al.: "Charge dynamics in underdoped Nd_<2-X>Ce_XCuO_4 : Pseudogap and related phenomena"Physical Review B. 69. 024504-1-024504-13 (2004)