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Metal -insulator -superconductor phase separation in the highly correlated organic conductors near the Mott transition.

Research Project

Project/Area Number 15540329
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Condensed matter physics II
Research InstitutionTohoku University

Principal Investigator

SASAKI Takahiko  Tohoku University, Institute for Materials Research, Associate Professor, 金属材料研究所, 助教授 (20241565)

Co-Investigator(Kenkyū-buntansha) YONEYAMA Naoki  Tohoku University, Institute for Materials Research, Research Associate, 金属材料研究所, 助手 (80312643)
Project Period (FY) 2003 – 2004
Project Status Completed (Fiscal Year 2004)
Budget Amount *help
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2004: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 2003: ¥2,100,000 (Direct Cost: ¥2,100,000)
Keywordsorganic conductor / Mott transition / phase separation / Infrared reflectance spectra / 金属絶縁体転移 / 赤外反射
Research Abstract

Systematic investigation of the electronic phase separation on macroscopic scale has been performed in the organic Mott system κ-(BEDT-TTF)_2[N(CN)_2]Br. Real space imaging of the phase separation is obtained by means of scanning micro-region infrared spectroscopy (SMIS) using the synchrotron radiation (SR). Experimental evidence of the electronic phase separation has been obtained on the single crystal surface of the organic Mott system κ-[(h-BEDT-TTF)_<1-x>(d-BEDT-TTF)_x]_2Cu[N(CN)_2]Br, of which band width is controlled by the substitution ratio x between the hydrogenated BEDT-TTF molecule (h-BEDT-TTF) and the deuterated one (d-BEDT-TTF). SMIS measurements using SR enable us to show the macroscopic size of the domain structure of the insulating and metallic regions. This finding does not exclude the possibility of the nano-scale inhomogeneity inside each domains or each scanning spot because the obtained spectrum may result in the average of nano-scale inhomogeneity in the measured spot. But close agreement between the previous results of NMR and magnetization and present results suggests that the phase separation occurs on macroscopic scale. The observation of the micro-meter scale phase separation is different from the recent findings of the nano-scale electronic inhomogeneity in the strongly correlated transition metal oxide system, which is a filling controlled Mott system. We therefore expect that the nano-scale intrinsic inhomogeneity appears in the filling controlled Mott system without thermodynamic phase transition, and the macroscopic inhomogeneity, if it comes, should accompany the critical phenomena like as the phase transition and non-equilibrium state in the band width controlled Mott system. The origin of the phase separation found in this study must be the bistability of the antiferromagnetic Mott insulator and superconducting phases just at the first order Mott transition.

Report

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

    (20 results)

All 2004 Other

All Journal Article (14 results) Publications (6 results)

  • [Journal Article] Imaging phase separation near the Mott boundary of the correlated organic superconductors κ-(BEDT-TTF)_2X2004

    • Author(s)
      T.Sasaki
    • Journal Title

      Phys.Rev.Lett. 92

    • 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] Electronic correlation in the infrared optical properties of the quasi-two-dimensional κ-type BEDT-TTF dimer system2004

    • Author(s)
      T.Sasaki
    • Journal Title

      Phys.Rev.B 69

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Disorder effect on the vortex pinning by the cooling-process control in the organic superconductor κ-(BEDT-TTF)_2Cu[N(CN)_2]Br2004

    • Author(s)
      N.Yoneyama
    • Journal Title

      J.Phys.Soc.Jpn. 73

      Pages: 184-189

    • NAID

      110001954709

    • 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] Impurity effect on the in-plane penetration depth of the organic superconductors κ-(BEDT-TTF)_2X (X=Cu(NCS)_2 and Cu[N(CN)_2]Br)2004

    • Author(s)
      N.Yoneyama
    • Journal Title

      J.Phys.Soc.Jpn. 73

      Pages: 1290-1296

    • NAID

      110001954846

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Infrared optical conductivity and the electronic phase diagram in the organic superconductors κ-(BEDT-TTF)_2X2004

    • Author(s)
      I.Ito
    • Journal Title

      J.Phys.IV France 114

      Pages: 321-322

    • 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] Substitution effect by deuterated donors on superconductivity in κ-(BEDT-TTF)_2Cu[N(CN)_2]Br2004

    • Author(s)
      N.Yoneyama
    • Journal Title

      J.Phys.Soc.Jpn. 73

      Pages: 1434-1437

    • NAID

      110001974399

    • 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] Imaging phase separation near the Mott boundary of the correlated organic superconductors _k-(BEDT-TTF)_2XImaging phase separation near the Mott boundary of the correlated organic superconductors _k-(BEDT-TTF)_2X2004

    • Author(s)
      T.Sasaki et al.
    • Journal Title

      Phys.Rev.Lett. 92

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Electronic correlation in the infrared optical properties of the quasi-two-dimensional κ-type BEDT-TTF dimer system2004

    • Author(s)
      T.Sasaki et al.
    • 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] Disorder effect on the vortex pinning by the cooling-process control in the organic superconductor κ-(BEDT-TTF)_2Cu[N(CN)_2]Br2004

    • Author(s)
      N.Yoneyama et al.
    • Journal Title

      J.Phys.Soc.Jpn. 73

      Pages: 184-189

    • NAID

      110001954709

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Impurity effect on the in-plane penetration depth of the organic superconductors κ-(BEDT-TTF)_2X (X=Cu(NCS)_2 and Cu[N(CN)_2]Br)2004

    • Author(s)
      N.Yoneyama et al.
    • Journal Title

      J.Phys.Soc.Jpn. 73

      Pages: 1290-1296

    • NAID

      110001954846

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Infrared optical conductivity and the electronic phase diagram in the organic superconductors κ-(BEDT-TTF)_2X2004

    • Author(s)
      I.Ito et al.
    • Journal Title

      J.Phys.IV France 114

      Pages: 321-322

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Substitution effect by deuterated donors on superconductivity in κ-(BEDT-TTF)_2Cu[N(CN)_2]Br2004

    • Author(s)
      N.Yoneyama et al.
    • Journal Title

      J.Phys.Soc.Jpn. 73

      Pages: 1434-1437

    • NAID

      110001974399

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Electronic correlation in the infrared optical properties of the quasi-two- dimensional κ-type BEDT-TTF dimer system2004

    • Author(s)
      T.Sasaki
    • Journal Title

      Phys.Rev.B 69

      Pages: 64508-64508

    • Related Report
      2004 Annual Research Report
  • [Journal Article] Impurity effect on the in-plane penetration depth of the organic superconductors κ-(BEDT-TTF)_2X (X=Cu(NCS)_2 and Cu[N(CN)_2Br)2004

    • Author(s)
      N.Yoneyama
    • Journal Title

      J.Phys.Soc.Jpn. 73

      Pages: 1290-1290

    • NAID

      110001954846

    • Related Report
      2004 Annual Research Report
  • [Publications] T.Sasaki et al.: "Shubnikov-de Haas effect in the quantum vortex liquid state of the organic super conductor κ-(BEDT-TTF)_2Cu(NCS)_2"Physical Review B. 67. 144521-1-144521-6 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] M.Lang et al.: "Phase-transition anomalies in the lattice response around 40 K in supercinducting κ-(BEDT-TTF)_2X"Synthetic Metals. 133-134. 107-110 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] N.Yoneyama et al.: "First-order vortex phase transition in κ-type BEDT-TTF organic superconductors"Synthetic Metals. 133-134. 223-224 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] T.Sasaki et al.: "Quantum magnetic oscillations in the quantum vortex liquid state ofκ-(BEDT-TTF)_2Cu(NCS)_2"Synthetic Metals. 137. 1187-1188 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] N.Yoneyama et al.: "Magnetic phase diagram and superconductivity in κ-type ET salts"Synthetic Metals. 137. 1205-1206 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] T.Sasaki et al.: "Electronic correlation in the infrared optical properties of the quasi-two-dimensionalκ-type BEDT-TTF dimer system"Physical Review B. 69. 06508-1-06508-7 (2004)

    • Related Report
      2003 Annual Research Report

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Published: 2003-04-01   Modified: 2020-05-15  

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