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Theoretical study of anomalous electronic states of vanadium oxides with pyroclore lattice structures

Research Project

Project/Area Number 14540324
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field 固体物性Ⅱ(磁性・金属・低温)
Research InstitutionChiba University

Principal Investigator

OHTA Yukinori  Chiba University, Department of Physics, Associate Professor, 理学部, 助教授 (70168954)

Project Period (FY) 2002 – 2004
Project Status Completed (Fiscal Year 2004)
Budget Amount *help
¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 2004: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2003: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2002: ¥1,000,000 (Direct Cost: ¥1,000,000)
Keywordsstrongly correlated electron systems / transition metal oxides / DMRG / spin-triplet superconductivity / orbital ordering / charge ordering / frustration / Hubbard model / 超伝導 / 金属絶縁体転移 / 擬1次元電子系 / 電荷ゆらぎ / 量子モンテカルロ / 準1次元系
Research Abstract

We have made theoretical and computational studies of strongly correlated electron systems, aiming in particular at elucidation of the mechanisms of the anomalous electronic properties of transition-metal oxides and molecular conductors. We have used the density-matrix renormalization group(DMRG) method for calculating the electronic states of pseudo-one-dimensional models in high accuracy. The main results obtained are the following.
1.We have clarified the mechanism of the charge and orbital ordering of the triangular-lattice Hollandite compound Bi_xV_8O_<16>.
2.We have clarified the mechanism of the orbital ordering and spin-singlet formation in pyroxene compound NaTiSi_2O_6.
3.We have clarified the nature of the anomalous spin excitations that appear in the states of large charge fluctuation.
4.We have elucidated the anomalous charge dynamics in the CuO double-chain systems.
5.We have proposed the novel mechanism of formation of the spin-gap liquid state that appears when the quantum melting of charge-ordered state occurs in the CuO double-chain systems.
6.We have calculated the precise electronic phase diagram of the ground state of the one-dimensional extended Hubbard model.
7.We have proposed the novel mechanism of the spin-triplet superconductivity that appears in the two-chain zigzag-bond Hubbard model.

Report

(4 results)
  • 2004 Annual Research Report   Final Research Report Summary
  • 2003 Annual Research Report
  • 2002 Annual Research Report
  • Research Products

    (36 results)

All 2005 2004 2003 2002 Other

All Journal Article (24 results) Publications (12 results)

  • [Journal Article] Phase Diagram of the t-U-V_1-V_2 Model at Quarter Filling2005

    • Author(s)
      S.Ejima 他
    • Journal Title

      Physical Review B 70(印刷中)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Ring Exchange Mechanism for Triplet Superconductivity in a Two-Chain Hubbard Model : Possible Relevance to Bechgaard Salts2005

    • Author(s)
      Y.Ohta 他
    • Journal Title

      Physical Review B 70(印刷中)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Phase Diagram of the t-U-V_1-V_2 Model at Quarter Filling2005

    • Author(s)
      S.Ejima, S.Nishimoto, F.Gebhard, Y.Ohta
    • Journal Title

      Phys.Rev.B (in press)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Ring Exchange Mechanism for Triplet Superconductivity in a Two-Chain Hubbard Model : Possible Relevance to Bechgaard Salts2005

    • Author(s)
      Y.Ohta, S.Nishimoto, T.Shirakawa, Y.Yamaguchi
    • Journal Title

      Phys.Rev.B (in press)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Dynamical Domain Walls and Spin-Peierls Order in Doped Antiferromagnets : Evidence from Exact Diagonalization of Small Clusters2004

    • Author(s)
      R.Eder, Y.Ohta
    • Journal Title

      Physical Review B 69

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Annual Research Report 2004 Final Research Report Summary
  • [Journal Article] Angle-Resolved Photoemission Spectra of the Stripe Phase in the Two-Dimensional t-J Model2004

    • Author(s)
      R.Eder, Y.Ohta
    • Journal Title

      Physical Review B 69

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Annual Research Report 2004 Final Research Report Summary
  • [Journal Article] Dynamical Domain Walls and Spin-Peierls Order in Doped Antiferromagnets : Evidence from Exact Diagonalization of Small Clusters2004

    • Author(s)
      R.Eder, Y.Ohta
    • Journal Title

      Phys.Rev.B 69

      Pages: 94433-94433

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Angle-Resolved Photoemission Spectra of the Stripe Phase in the Two-Dimensional t-J Model2004

    • Author(s)
      R.Eder, Y.Ohta
    • Journal Title

      Phys.Rev.B 69

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Anomalous Behaviors of the Charge and Spin Degrees of Freedom in the CuO Double Chains of PrBa_2Cu_4O_82003

    • Author(s)
      S.Nishimoto, Y.Ohta
    • Journal Title

      Physical Review B 68

    • NAID

      110002062136

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Excitations in the Coupled Spin-Pseudospin Model for Quarter-Filled Ladders2003

    • Author(s)
      S.Ejima, T.Nakaegawa, Y.Ohta
    • Journal Title

      Physica B 328

      Pages: 105-107

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Interplay between Spin and Charge Excitations in the Coupled Spin-Pseudospin Systems2003

    • Author(s)
      Y.Ohta, S.Ejima, T.Nakaegawa
    • Journal Title

      Journal of Lw temperature Physics 131

      Pages: 239-243

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Optical Conductivity in the CuO Double chains of OrBa_2Cu_4O_82003

    • Author(s)
      Y.Ohta, R.Amasaki, Y.Shibata
    • Journal Title

      Journal of Low Temperature Physics 131

      Pages: 245-249

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Anomalous Spin Excitations in a Coupled Spin-Pseudospin Model for Anisotropic Hubbard Ladders at Quarter Filling2003

    • Author(s)
      Y.Ohta 他
    • Journal Title

      Physica B 329-333

      Pages: 996-997

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Charge Fluctuation in the CuO Double Chains of PrBa_2Cu_4O_82003

    • Author(s)
      Y.Ohta, R.Amasaki, Y.Shibata
    • Journal Title

      Physica B 329-333

      Pages: 1467-1468

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Anomalous Behaviors of the Charge and Spin Degrees of Freedom in the CuO Double Chains of PrBa_2Cu_4O_82003

    • Author(s)
      S.Nishimoto, Y.Ohta
    • Journal Title

      Phys.Rev.B 68

      Pages: 235114-235114

    • NAID

      110002062136

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Interplay between Spin and Charge Excitations in the Coupled Spin-Pseudospin Systems2003

    • Author(s)
      Y.Ohta, S.Ejima, T.Nakaegawa
    • Journal Title

      J.Low Temp.Phys. 131

      Pages: 239-243

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Optical Conductivity in the CuO Double Chains of PrBa_2Cu_4O_82003

    • Author(s)
      Y.Ohta, R.Amasaki, Y.Shibata
    • Journal Title

      J.Low Temp.Phys. 131

      Pages: 245-249

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Anomalous Spin Excitations in a Coupled Spin-Pseudospin Model for Anisotropic Hubbard Ladders at Quarter Filling2003

    • Author(s)
      Y.Ohta, S.Ejima, Y.Shibata, T.Nakaegawa
    • Journal Title

      Physica B 329-333

      Pages: 996-997

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Charge and Orbital Ordering in the Triangular-Lattice t_<2g>-Orbital System in One Dimension : a Possible Ground State of Bi_xV_8O_<16>2002

    • Author(s)
      Y.Shibata, Y.Ohta
    • Journal Title

      Journal of the Physical Society of Japan 71

      Pages: 513-518

    • NAID

      110001971579

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Optical Conductivity in the CuO Double Chains of PrBa_2Cu_4O_8:Consequences of Charge Fluctuation2002

    • Author(s)
      R.Amasaki, Y.Shibata, Y.Ohta
    • Journal Title

      Physical Review B 66

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Theory of Charge and Orbital Ordering in the One-Dimensional Triangular-Lattice Vanadate Bi_xV_8O_<16>2002

    • Author(s)
      Y.Ohta, Y.Shibata
    • Journal Title

      Journal of the Physical Society of Japan (Suppl.) 71

      Pages: 181-183

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Charge and Orbital Ordering in the Triangular-Lattice t_<2_g>-Orbital System in One Dimension : A Possible Ground State of Bi_xV_8O_<16>2002

    • Author(s)
      Y.Shibata, Y.Ohta
    • Journal Title

      J.Phys.Soc.Jpn. 71, No.2

      Pages: 513-518

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Optical Conductivity in the CuO Double Chains of PrBa_2Cu_4O_8 : Consequences of Charge Fluctuation2002

    • Author(s)
      R.Amasaki, Y.Shibata, Y.Ohta;
    • Journal Title

      Phys.Rev.B 66

      Pages: 12502-12502

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Theory of Charge and Orbital Ordering in the One-Dimensional Triangular-Lattice Vanadate Bi_xV_8O_<16>2002

    • Author(s)
      Y.Ohta, Y.Shibata
    • Journal Title

      J.Phys.Soc.Jpn. 71(Suppl.)

      Pages: 181-183

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Publications] S.Nishimoto, Y.Ohta: "Anomalous Behaviors of the Charge and Spin Degrees of Freedom in the CuO Double Chains of PrBa2Cu4O8"Physical Review B. 68・23. 235114-1-235114-9 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] Y.Ohta, S.Ejima, T.Nakaegawa: "Interplay between Spin and Charge Excitations in the Coupled Spin-Pseudospin Systems"Journal of Low Temperature Physics. 131. 239-243 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] Y.Ohta, R.Amasaki, Y.Shibata: "Optical Conductivity in the CuO Double Chains of PrBa2Cu4O8"Journal of Low Temperature Physics. 131. 245-249 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] Y.Ohta, S.Ejima, Y.Shibata, T.Nakaegawa: "Anomalous Spin Excitations in a Coupled Spin-Pseudospin Model for Anisotropic Hubbard Ladders at Quarter Filling"Physica B. 329-333. 996-997 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] Y.Ohta, R.Amasaki, Y.Shibata: "Charge Fluctuation in the CuO Double Chains of PrBa2Cu4O8"Physica B. 329-333. 1467-1468 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] R.Eder, Y.Ohta: "Dynamical Domain Walls and Spin-Peierls Order in Doped Antiferromagnets : Evidence from Exact Diagonalization of Small Clusters"Physical Review B. 69. 094433-1-094433-4 (2004)

    • Related Report
      2003 Annual Research Report
  • [Publications] Y.Shibata, Y.Ohta: "Charge and Orbital Ordering in the Triangular-Lattice t_<2g>-Orbital System in One Dimension : A Possible Ground State of Bi_xV_8O_<16>"Journal of the Physical Society of Japan. 71,No.2. 513-518 (2002)

    • Related Report
      2002 Annual Research Report
  • [Publications] R.Amasaki, Y.Shibata, Y.Ohta: "Optical Conductivity in the CuO Double Chains of PrBa_2Cu_4O_8 : Consequences of Charge Fluctuation"Physical Review B. 66. 012502 (2002)

    • Related Report
      2002 Annual Research Report
  • [Publications] S.Ejima, T.Nakaegawa, Y.Ohta: "Excitations in the Coupled Spin-Pseudospin Model for Quarter-Filled Ladders"Physica B. 328. 105-107 (2003)

    • Related Report
      2002 Annual Research Report
  • [Publications] Y.Ohta, S.Ejima, T.Nakaegawa: "Interplay between Spin and Charge Excitations in the Coupled Spin-Pseudospin Systems"Journal of Low Temperature Physics. 133. No.3-4. 239-243 (2003)

    • Related Report
      2002 Annual Research Report
  • [Publications] Y.Ohta, R.Amasaki, Y.Shibata: "Optical Conductivity in the CuO Double Chains of PrBa_2Cu_4O_8"Journal of Low Temperature Physics. 133. No.3-4. 245-249 (2003)

    • Related Report
      2002 Annual Research Report
  • [Publications] Y.Ohta, S.Ejima, Y.Shibata, T.Nakaegawa: "Anomalous Spin Excitations in a Coupled Spin-Pseudospin Model for Anisotropic Hubbard Ladders at Quarter Filling"Physica B. (印刷中). (2003)

    • Related Report
      2002 Annual Research Report

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Published: 2002-04-01   Modified: 2020-05-15  

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