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2000 Fiscal Year Final Research Report Summary

PRESSURE CONTROL OF ORGANIC CONDUCTOR-DISCOVERY OF NEW TYPE OF NARROW GAP SEMICONDUCTORS

Research Project

Project/Area Number 10304031
Research Category

Grant-in-Aid for Scientific Research (A).

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

Principal Investigator

KAJITA Koji  TOHO UNIVERSITY, FACUILTY OF SCIENCE, PROFESSOR, 理学部, 教授 (50011739)

Co-Investigator(Kenkyū-buntansha) TAMURA Masahumi  THE INSTITUTE OF PHYSICAL AND CHEMICAL RESEARCH, SENIOR RESEARCHER, 先任研究員 (00231423)
NISHIO Yutaka  TOHO UNIV., FACULTY OF SCIENCE, ASSOCIATED PROFESSOR, 理学部, 助教授 (20172629)
Project Period (FY) 1998 – 2000
KeywordsORGANIC CONDUCTOR / MAGNETO-TRANSPORT / HALLEFFECT / NARROW GAP SEMICONDUCTOR / PRESSURE EFFECT / UNIAXIAL STRAIN
Research Abstract

Many organic conductors exhibit temperature-independent conductivity. Usually, they are considered to be dirty metals of which the electrical conduction is governed by impurity scattering. One of the main results of this investigation is the finding of pure organic conductors which shows temperature independent conductivity. In those conductors, both carrier density and mobility vary strongly with temperature. Nevertheless, we see temperature independent conduction because the effect of the change in the density and mobility just cancel out. Up to now, we know no other materials with such curious character both among organic and inorganic conductors. According to the density change at low temperatures, we found that they are semiconductors with extremely narrow energy gap.
Organic conductors such as α-(BEDT-TTF)_2I_3, α-(BEDT-TSeF)_2I_3, O-(BEDT-TTF)_2I_3 and α-(BEDT-STF)_2I_3 belongs to this category of materials in case they are placed under high pressures.
Another characteristic behavior of those materials is observed at low temperature under magnetic field. The property of carriers varies with increasing field. There are three steps of change. At low field limit, carriers have the mass of about 0.02m. where m is the free electron mass. In the intermediate field, the mass rises to a value close to m. In the high fields such as 10T, carrier mass looks to be much heavier.

  • Research Products

    (31 results)

All Other

All Publications (31 results)

  • [Publications] 森初果: "New Organic Conduction Containing Mapretic I on of Cu (II) α^n-(BEDT-TTF)_2Cu(SCN)_4"Chemistry Letters. 505-506 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 梶田晃示: "an ulthe Narrow gap Organic Semiconduction in the Magnetic Field"Proc.4th Int.Symprosium on aduanced Physical Field. 79-81 (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 田嶋尚也: "anomalous Magnetic transfors of a Highly Medical Electron Sptem in α-(BEDT-TTF)_2I_3"Synthetic Metals. 103. 1960-1960 (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 田嶋尚也: "Finding of a New Organic Semiconductor with an Extremely Narow Gap"Synthetie Metals. 103. 1958-1959 (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 西尾豊: "Specific Heat and Metal-Ineulator Transition of (BEDT-TTF)_2MZ_n(SCN)_4(M=Cs,Rb)"Synthetic Metals. 103. 1907-1908 (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 大島勇吾: "Cyclotron Reseonance Study of θ-(BEDT-TTF)_2I_3"Synthetic Metals. 103. 1919-1920 (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 塩見大輔: "Possible super-high-spin cluster in the anptal of a Nauel Nitroxide Radicals as Studied by FT Palsied ESR"Mol.Cupt.and Liq.Cryst.. 335. 359-369 (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 田嶋尚也: "Transport Property of an Organic Conductor α-(BEDT-TTF)_2I_3 under High Pressure-Discovery of a Novel type-"J.Phys.Sac.Jpn.. 69. 543-551 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 森初果: "Uiscontinaous Change of metal-Insulator Transition of the alluyed θ-System : θ-(BEDT-TTF)_2(C_<xy>Rb_<1-x>)Zn(SCN)_4"J.Phys.Sac.Jpn.. 69. 1751-1756 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 西尾豊: "Thermal study of (DME-DCNQI)_2Cu System-Mechanism of Reentrant Metal-insulator Transition"J.Phys.Sca.Jpn.. 69. 1414-1422 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 森初果: "Bandwidth and Band Fidling Contral in Organic Conductars"Synthetic Metals. (印刷中).

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 西尾豊: "Anomalons Specific Heart of (DEe-DCNQI-d_2[1,1;0]_<1-x>d_4[2,2;0])_2Cu-System"Synthetic Metals. (印刷中).

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 笠原茂: "Hynamical Behavious of Vartices in a Layord Supereonductor-K-(BEDT-TTF)_2Ca(NCS)_2"Synthetic Metals. (印刷中).

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 田嶋尚也: "Transport property of α-(BEDT-TTF)_2I_3 under high Pressure-Ultra Narrow Gap Semiconductor-"Synthetic Metals. (印刷中).

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 西尾豊: "DCNQI系リエントラント金属-絶縁体の熱的研究"熱測定. 25. 154-161 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] M.Mori: "New Organic Conductor containing Magnetic Ion of Cu(II) ; α"-(BEDT-TTF)_2KCu(SCN)_4"Chemistry Letters. 505-506 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K.Kajita: "An Ultra Narrow gap Organic Semiconductor in the Magnetic field."Proc.4th Int.symposium on advanced physical field. 79-81 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] N.Tajima: "Anomalous Magnetotransport of a Highly Mobile electron system in α-(BEDT-TTF)_2I_3"Synhtetic Metals. 103. 1960 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] N.Tajima: "Finding of a New Organic Semiconductor with an Extremely Narrow Gap"Synthetic Metals. 103. 1958-1959 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y.Nishio: "Specific Heat and Metal-Insulator Transition of (BEDT-TTF)_2MZn(SCN)_4 (M=Cs, Rb)"Synthetic Metals. 103. 1907-1908 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y.Oshima: "Cyclotron resonance study of θ-(BEDT-TTF)_2I_3"Synthetic Metals. 103. 1919-1920 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] D.Shiomi: "Possible superhigh-Spin Cluster in the Crystal of a Novel Nitronyl Nitroxide Radical as studied by FT Pulsed ESR"Mol.Cryst. and Liq.Cryst. 335. 359-369 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] N.Tajima: "Transport Property of an Organic Conductor α-(BEDT-TTF)_2I_3 under High Pressure-Discovery of a Novel type of Conductor-"J.Phys.Soc.Jpn.. 69. 543-551 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] H.Mori: "Discontinuous Change of Metal-Insulator Transition of the Alloyed θ-System : θ-(BEDT-TTF)_2(Cs_xRb_<1-x>)Zn(SCN)_4"J.Phys.Soc.Jpn.. 69. 1751-1756 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y.Nishio: "Thermal Study of (DMe-DCNQI)_2Cu system-Mechanism of Reentrant Metal-Insulator Transition-."J.Phys soc.Jpn.. 69. 1414-1422 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] H.Mori: "Bandwidth and band filling control in Organic conductors"Syntnetic Metals. (in press).

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y.Nishio: "Anomalous specific heat of (DMe-DCNQI-d_2 [1,1 ; 0] _<1-x>d_4 [2,2 ; 0] _x)_2Cu-system"Synthetic Metals. (in press).

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] S.Kasahata: "Dynamical behavior of vortices in a layered superconductor κ-(BEDT-TTF)_2Cu(NCS)_2"Synthetic Metals. (in press).

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] N.Tajima: "Transport property of α-(BEDT TTF)_2I_3 under high pressure ultra narrow gap semiconductor"Synthetic Metal. (in press).

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M.Tamura: "π-f composite metals"Synthetic Metals. (in press).

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y.Nishio: "Thermomechanical Study of Metal-Insulator Transition of DCNQI-System (in Japanese)"Netusokutei. 25. 154-1161 (1998)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 2002-03-26  

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