Updated on 2024/06/17


Faculty of Science and Engineering
Job title
Professor Emeritus
博士(理学) ( 早稲田大学 )

Professional Memberships







Research Areas

  • Semiconductors, optical properties of condensed matter and atomic physics / Magnetism, superconductivity and strongly correlated systems

Research Interests

  • 高温超伝導、強相関系、結晶成長



  • Crystal growth and anisotropic transport properties of high-Tc superconductors

    T. Watanabe, T. Fujii, A. Matsuda

    Recent Res. Devel. Phys,   5   51 - 86  2004

  • Structural Study of the Inhomogeneous Charge Distribution of Inequivalent CuO2 Planes in a Bi2.1Sr1.9Ca2Cu3O10+d

    T. Watanabe, T. Fujii, A. Matsuda

    J. Phys. Soc. Jpn   72 ( 11 ) 2924 - 2929  2003.11  [Refereed]

  • Observation of Band Renormalization Effects in Hole-Doped High-Tc Superconductor

    T. Sato, H. Matsui, T. Takahashi, H. Ding, H.-B. Yang, S.-C. Wang, T

    Phys. Rev. Lett.   91 ( 15 ) 157003  2003.10  [Refereed]

  • Systematics of electronic structure and interations in Bi2Sr2Can-1CunO2n+4(n=1-3) by angle-resolved photoemission spectroscopy

    H. Matsui, T. Sato, T. Takahashi, H. Ding, H.-B. Yang, S.-C. Wang, T

    Phys. Rev. B   67 ( 6 ) 060501  2003.08

  • Gap Inhomogeneity, Phase separation and Pseudogap in Bi2Sr2CaCu2O8+d

    A. Matsuda, T. Fujii, T. Watanabe

    Phyica C   388-389   207 - 208  2003  [Refereed]

  • Superconducting gap and pseudogap in Bi2Sr2Ca2Cu3O10+d by short-pulse interlayer tunneling spectroscopy

    Y. Yamada, K. Anagawa, T. Fujii, T. Watanabe, A. Matsuda, T. Shibauchi, M. Suzuki

    Phyica C   388-389   285 - 286  2003  [Refereed]

  • Low Energy Excitation and Scaling in Bi2Sr2Can-1CunO2n+4 (n=1-3): Angle-Resolved Photoemission Spectroscopy

    T. Sato, H. Matsui, S. Nishina, T. Takahashi, T. Fujii, T. Watanabe, A. Matsuda

    Phys. Rev. Lett.   89 ( 6 ) 67005 - 67008  2002.08  [Refereed]

  • Large in-plane anisotropy on ressistivity and thermopower in the misfit layered oxide Bi2-xPbxSr2Co2Oy

    T. Fujii, I. Terasaki, T. Watanabe, A. Matsuda

    Jpn. J. Appl. Phys.   41 ( 7 ) L783 - L786  2002.07  [Refereed]

  • Doping dependence of anisotropic resistivities in trilayered superconductor Bi2Sr2Ca2Cu3O10+d

    T. Fujii, T. Watanabe, I. Terasaki, A. Matsuda

    Phys. Rev. B   66 ( 2 ) 024507  2002.07  [Refereed]

  • Effect of silver addition on structure and electrical properties of the spin ladder compound La2Cu2O5 single crystals

    C Sekar, T Watanabe, A Matsuda, H Shibata, Y Zenitani, J Akimitsu

    JOURNAL OF CRYSTAL GROWTH   233 ( 3 ) 466 - 472  2001.12  [Refereed]

     View Summary

    We have investigated the influence of silver on crystallization and oxygenation or the spin ladder compound La2Cu2O5 (four-leg) single crystals. Large La2Cu2O5 single crystals were successfully grown from charges containing A920 by a self-flux method. Electrical resistivity of the silver grown La2Cu2O5 single crystals (parallel tob-axis) has been found to be about three orders of magnitude lower when compared with the similar crystals grown without silver. Characterizations with optical microscope, XRD, EPMA and HRTEM indicate that the silver does not exist either in free state in the crystal or in the crystal lattice. The results show that the silver facilitates oxygenation in La2Cu2O5 crystals during their growth. (C) 2001 Elsevier Science B.V. All rights reserved.

  • Influence of substrates on epitaxial thin films of high-temperature superconductors

    H. Sato, M. Naito, A. Tsukada, S. Karimoto, A. Matsuda

    Physica C   362   189 - 194  2001.09  [Refereed]

  • Novel Approaches to Crystalize Materials with Nallow Liquidas Lines:

    T. Watanabe, C.Sekar, T. Fujii, A. Matsuda

    J. of Cryst. Growth   229   316 - 320  2001.07

  • Crystal growth, structure, and transport properties of the five-leg spin ladder compound La8Cu7O19

    C Sekar, T Watanabe, A Matsuda, H Shibata, Y Zenitani, J Akimitsu

    JOURNAL OF SOLID STATE CHEMISTRY   156 ( 2 ) 422 - 427  2001.02  [Refereed]

     View Summary

    The crystallization region of La8Cu7O19 exists in a narrow temperature (1045-1050 degreesC) and composition range (1:4.5-1:5.0; La2O3:CuO molar ratio) in the La2O3-CuO system in an air ambient. In this narrow range, we have succeeded in growing large La8Cu7O19 single crystals, for the first time, by a modified slow cooling method. Single-crystal X-ray diffraction analysis reveals that La8Cu7O19 crystallizes in a monoclinic structure with space group C2/c and has the lattice parameters a = 13.82(7) Angstrom, b = 3.734(8) Angstrom, c = 34.77(10) Angstrom, and beta = 99.3(4)degrees. The electrical transport behavior of the as-grown and hole-doped La8Cu7O19 single crystals are semiconducting. A lowest resistivity of 11.0 m Omega -cm is measured at 293 K along the ladder direction (// b-axis) for the hole-doped samples. (C) 2001 Academic Press.

  • Comparative study of transport properties of Bi2Sr2Ca2Cu3O10+d and Bi2Sr2CaCu2O8+d single crystals

    T. Fujii, T. Watanabe, A. Matsuda

    Phyica C   357-360   173 - 176  2001  [Refereed]

  • Superconductor-Insulator transition and transport property of underdoped YBa2Cu3Oy single crystals

    K. Semba, A. Matsuda

    Phys. Rev. Lett.   86 ( 3 ) 496 - 499  2001.01  [Refereed]

  • Single Crystal growth of Bi2Sr2Ca2Cu3O10+d (Bi-2223) by TSFZ method

    T. Fujii, T. Watanabe, A. Matsuda

    J. of Cryst. Growth   223   175 - 180  2001.01

  • Study of pseudogap phenomena by STM and other probes

    A. Matsuda, S. Sugita, T. Fujii, T. Watanabe

    Journal of Physics and Chemistry of Solids   62 ( 1-2 ) 65 - 68  2001

     View Summary

    The temperature and doping dependence of the tunneling spectrum of Bi2.1Sr1.9CaCu2Ox single crystals was obtained by using a low-temperature scanning tunneling microscope. Above Tc, for x≤8.27, the tunneling density of states shows a clear gap-like feature with a larger gap value than the superconducting one, while for x&gt
    8.27, it shows the feature expected from the conventional superconducting fluctuation (SCF). We determined the SCF component in the static susceptibility (χ). By subtracting the effect of the SCF from χ, we confirmed that the two pseudogap phase boundaries determined by the tunneling and χ coincide with each other.



  • Anisotropy in the Superconducting State and c-axis resistivity of Precisely Oxygen Cotrolled Bi2Sr2CaCu2O8+d Single Crystals

    T. Fujii, T. Watanabe, A. Matsuda

    Phyica C   341-348   1873 - 1874  2000.11  [Refereed]

  • La-214 Thin Films under Eptaxial Strain

    H. Sato, A. Tsukada, M. Naito, A. Matsuda

    Phyica C   341-348   1767 - 1768  2000.11  [Refereed]

  • Pseudogap in Bi2Sr2CaCu2O8+d studied by measureing anisotropic susceptibilities and out-of-plane transport

    T. Watanabe, T. Fujii, A. Matsuda

    Phys. Rev. Lett.   84 ( 25 ) 5848 - 5851  2000.07

  • Absence of "1/8 anomaly" in Strained Thin Films of La2-xBaxCuO4+d

    H. Sato, A. Tsukada, M. Naito, A. Matsuda

    Phys. Rev. B   62 ( 2 ) R799 - R802  2000.07  [Refereed]

  • La2-xSrxCuOy epitaxial thin films (x-0 to 2): Structure, strain, and superconductivity

    H. Sato, A. Tsukada, M. Naito, A. Matsuda

    Phys. Rev. B   61 ( 18 ) 12447 - 12456  2000.05  [Refereed]

  • Transport Property and Quantum Critical Point of Underdoped YBa2Cu3O6+x

    K. Semba, A. Matsuda, M. Mukaida

    Advances in Sci. & Tech.   29   121 - 128  2000

  • Crystal growth and characterization of the 4-leg spin ladder compound La2Cu2O5

    C. Sekar, T. Watanabe, A. Matsuda

    Journal of Crystal Growth   212 ( 1 ) 142 - 147  2000

     View Summary

    Crystallization of La2Cu2O5 has been investigated in the La2O3-CUO system for various starting compositions both in air and oxygen atmospheres. In air, we find that there exists a new region of crystallization of La8Cu7O19 phase, just above that of La2Cu2O5. However, this region vanishes completely in flowing-oxygen atmosphere. By utilizing this, large single crystals of the 4-leg spin-ladder compound La2Cu2O5 have been successfully grown from CuO flux by the slow cooling method. Room-temperature resistivity parallel to the ladder direction (∥b) of the as-grown crystals is estimated to be 1.7×103 Ω cm. A significant decrease in the resistivity (798 mΩ cm at 300 K) is observed upon hole doping by means of high oxygen pressure annealing (approximately 400 atm) using a hot isostatic pressing furnace. However, no transition was observed from the semiconducting behavior.



  • Pseudogap in Bi2Sr2CaCu2O8+d studied by measuring anisotropic suscptibilities and out-of-plane transport

    T. Watanabe, T. Fujii, A. Matsuda

    Phyica C   341-348   931 - 932

  • Crystal growth and transport properties of spin ladder compounds La4+4nCu8+2nO14+8n(n=2,3)

    T. Watanabe, C.Sekar, H. Shibata, A. Matsuda, Y. Zenitani, J. Akimitsu

    Phyica C   357-360   380 - 383

  • Microwave-induced zero-current crossings in Bi2Sr2CaCu2O8+y intrinsic Josephson junctions

    T. Shibauchi, J. Hashimoto, K. Fujita, T. Watanabe, A. Matsuda, M. Suzuki

    Phyica C   388-389   461 - 462

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Internal Special Research Projects

  • 強相関電子系における不均一電子状態の低音STMによる研究


     View Summary

     本研究は、低温STMを用いて高温超伝導体の超伝導状態で観測される超伝導ギャップの不均一分布の起源をさぐる目的で企画された。担当者は2004年度新任で、本計画に使用する低温STM装置は、前任の研究機関(NTT物性科学基礎研究所)より貸与を受け、早稲田大学に移設・再構築する予定であった。当初の研究の企画は、再稼働させた実験装置をベースに、装置を改造し、不均一効果に対する結晶の歪み効果を調べる計画になっている。計画自体は、1年で成果を出せる性格のものでなく、数年間かけて実施することが前提になる。 担当者が早稲田大学に着任後、実験装置の移設が実現したのが2004年9月であり、移設後順次電源工事、ガス配管工事、測定用ネットワーク構築などのユーティリティ接続作業を行い、2004年11月頃に常温用STM装置、さらに12月頃にSTM装置一号機を稼働状態にした。本特定課題で提供された資金のほとんどは、以上の実験装置再稼働のための機器購入や装置改修にあてられた。その後、常温用STM装置においては、超高真空下で、(1)高温超伝導体のBi-2223(Bi2Sr2Ca2Cu3O10+d), (2) Bi系層状Co酸化物(Bi2Sr2Co2Ox)、の表面観測を開始し、結果はまだ予備的であるが、何れも格子像を得る事に成功した。両物質とも格子像を得る事自体世界初の試みである。特に、後者のCo層状酸化物は、電子状態の解明が進んでおらず、新たな発見が期待される。今後さらに精度の高い観測を行い、低温測定と合わせて電子状態の解明を進める。低温用STMについても、稼働状態になって以来、液体窒素温度77Kでの測定に成功し、格子像も徐々に取れるようになってきたが、稼働を始めてからまだ日が浅く、物理的に意味のある成果はまだ出ていない。装置的にも、まだ完全な状態とは言えず、電気的ノイズの低減が重要な課題である。その後、本来の特定課題の研究テーマである、不均一性と歪み効果の関係について調べてゆく予定である。