Organic Metals and Superconductors Based on BEDT-TTF

  • Hatsumi Urayama
  • Hideki Yamochi
  • Gunzi Saito
  • Kokichi Oshima
Conference paper


A metal, (BEDT-TTF)3Br2(H2O)2, and a superconductor, (BEDT-TTF)2 Cu(NCS)2, based on BEDT-TTF (bis(ethylenedithiolo)tetratniafulvalene, Fig. 1) are presented. The BEDT-TTF complex with a small anion, Br , has been synthesized with the accidental inclusion of H2O which may stabilize the crystallization. The given black plate crystal, (BEDT-TTF)oBr2(H2O)2, is isostructual to (BEDT-TTF)3(ClO4)2. Two bromide anions and two water molecules, Br 2(H2O)2, form a planar square cluster with hydrogen bonds. This cluster constructs a insulating sheet which is sandwiched by two-dimensional BEDT-TTF sheets. The electrical resistivity shows the metallic behavior down to 185 K and transforms to semiconducting system, which is also confirmed by the ESR measurements. (BEDT-TTF)2Cu(NCS)2 was found to be the first ambient pressure organic superconductor with the Tc higher than 10 K. The salt has a layered structure which is composed of donor and anion sheets. The packing pattern of donors of the Cu(NCS)2 salt is nearly analogous to K-(BEDT-TTF)2I3. In anion layers CuI is trigonal coordinated to two N atoms and one S atom to construct a one-dimensional planar polymer. The valence state of CuI was observed by ESCA at 298 K and ESR at 298-4 K. One broad Lorentzian ESR signal ascribed to a BEDT-TTF cation radical was obtained. The g-values are independent of temperature, while the linewidth shows broadening with lowering temperature even though the resistivity decreases below 90 K. The ESR magnetic susceptibility is constant down to 90 K, which is suggesting Pauli-like paramagnetism. The thermopower is anisotropic in the two-dimensional be plane, which is originated from the anisotropy of the band structure.


Electrical Resistivity Metallic Behavior Spin Susceptibility Anion Layer Packing Pattern 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    E. B. Yagubskii, I. F. Shchegolev, V. N. Laukhin, P. A. Kononovich, M. V. Karatsovnic, A. V. Zvarykiha, and L. I. Buravov, Pis’ma Zh. Eksp. Theor. Fiz. 39 1984 12Google Scholar
  2. 1a.
    H. H. Wang, H. A. Beno, V. Geiser, M. A. Firestone, K. S. Webb, L. Nunez, G. W. Grabtree, K. D. Carlson, J. M. Williams, L. J. Azevedo, J.F. Kwak, J. E. Schirber, Inorg. Chem., 24 (1985) 2466CrossRefGoogle Scholar
  3. 1b.
    J. M. Williams, H. H. Wang, M. A. Beno, T. J. Emge, L. M. Sowa, P. T. Copps, F. Behroozi, L. N. Hall, K. D. Carlson, G. W. Crabtree, Inorg. Chem., 23 1984) 3839CrossRefGoogle Scholar
  4. 1c.
    R. N. Lynbovskaya, R. B. Lyubovskii, R. P. Shibaeva, M. Z. Aldoshina, L. M. Gol’denberg, L. P. Rozenber, M. L. Khidekel, and Yu. F. Shul’pyakov, Pis’ma Zh. Eksp. Teor. Fiz., 42.(1985) 380Google Scholar
  5. 1d.
    R. N. Lyubovskaya, E. A. Zhilyaeva, A. V. Zvarykina, V. N. laukhin, R. B. Lyubovskii, and S. I. Pesotskii, ibid., 45 (1987) 416.ADSGoogle Scholar
  6. 2.
    H . Urayama, G. Saito, A. Kawamoto, and J. Tanaka, Chem. Lett., 1987, 1753Google Scholar
  7. 2a.
    H. Urayama, G. Saito, T. Sugano, M. Kinoshita, A. Kawamoto, and J. Tanaka, Synth. Met., in press.Google Scholar
  8. 3.
    H. Urayama, H. Yamochi, G. Saito, K. Nozawa, T. Sugano, M. Kinoshita, S. Sato, K. Oshima, A. Kawamoto, and J. Tanaka, Chem. Lett., 1988 55Google Scholar
  9. 3a.
    H. Urayama, H. Yamochi, G. Saito, T. Sato, T. Sugano, M. Kinoshita, A. Kawamoto, J. Tanaka, T. Inabe, T. Mori, Y. Maruyama, H. Inokuchi, and K. Oshima, Synthe. Met. in press and references cited in.Google Scholar
  10. 4.
    T. Mori and H. Inokuchi, Chem. Lett., 1987 1657Google Scholar
  11. 4a.
    D. Chasseau, D. Watkin, M. Rosseinsky, M. Kurmoo, and P. Day, Synth. Met., 24 (1988)Google Scholar
  12. 5.
    H. Kobayashi, R. Kato, T. Mori, A. Kobayashi, Y. Sasaki, G. Saito, T. Enoki, and H. Inokuchi, Chem. Lett., 1984, 179.Google Scholar
  13. 6.
    H. Kuroda, K. Yakushi, H. Tajima, and G. Saito, Mol. Cryst. Liq. Cryst. 125 (1985) 135.CrossRefGoogle Scholar
  14. 7.
    T. Sugano, G. Saito, and M. Kinoshita, Phy. Rev. B 34 (1986) 117.ADSCrossRefGoogle Scholar
  15. 8.
    T. Enoki, K. Imaeda, M. Kobayashi, H. Inokuchi, and G. Saito, Phys. Rev. B 33 (1986) 1553.ADSCrossRefGoogle Scholar
  16. 9.
    P. M. Chaikin and J. F. Kwak, Rev. Sci. Instrum., 46 (1975) 218.ADSCrossRefGoogle Scholar
  17. 10.
    The results of Agx(SCN)y and Agx’ (SeCN)y’ salts were presented at the symposium of Annual Meeting of Chemical Society of Japan, Tokyo, April 1987. The crystal data of (BEDT-TTF)-Agx (SCN)y are: orthorhombic, a=11.590(1), b=40.132(4), c=4.254(0 Å, and V=1978.9 (6) Å3. The diffuse track along the c axis measured by oscillation photographs was detected.Google Scholar
  18. 11.
    D. T. Cromer, J. Phys. Chem., 61. (1957) 1388.CrossRefGoogle Scholar
  19. 12.
    A. Abragam and B. Bleaney, Electron Paramagnetic Resonance of Transiiton Ions, (Clawrendon, Oxford, 1970).Google Scholar
  20. 13.
    R. J. Elliot, Phys. Rev. 96 (1954) 266ADSCrossRefGoogle Scholar
  21. 13a.
    A. W. Overhauser, ibid., 89 (1953) 689.ADSMATHGoogle Scholar
  22. 14.
    Int. Conf. on Electronics of Organic Materials, ELORMA 1987 Tashkent; K. Mortensen, J. M. Williams, and H. H. Wang, Solid State Commun., 56 (1985) 105CrossRefGoogle Scholar
  23. 14a.
    V. A. Merzhanov, E. E. Kostyuchenko, 0. E. Fabrt, I. F. Shchegolv, and E. B. Yagubskii, Zh. Eksp. Teore. Fiz., 89 (1985) 292.ADSGoogle Scholar
  24. 15.
    T. Mori and H. Inokuchi, submitted to J. Phy. Soc. Jpn.Google Scholar

Copyright information

© Springer Japan 1989

Authors and Affiliations

  • Hatsumi Urayama
    • 1
  • Hideki Yamochi
    • 1
  • Gunzi Saito
    • 1
  • Kokichi Oshima
    • 2
  1. 1.Institute for Solid State PhysicsThe University of TokyoMinato-ku, Tokyo, 106Japan
  2. 2.Cryogenic CenterThe University of TokyoBunkyo-ku, Tokyo, 113Japan

Personalised recommendations