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An organic thyristor


Thyristors are a class of nonlinear electronic device that exhibit bistable resistance—that is, they can be switched between two different conductance states1. Thyristors are widely used as inverters (direct to alternating current converters) and for the smooth control of power in a variety of applications such as motors and refrigerators. Materials and structures that exhibit nonlinear resistance of this sort are not only useful for practical applications: they also provide systems for exploring fundamental aspects of solid-state and statistical physics. Here we report the discovery of a giant nonlinear resistance effect in the conducting organic salt2 θ-(BEDT-TTF)2CsCo(SCN)4, the voltage-current characteristics of which are essentially the same as those of a conventional thyristor. This intrinsic organic thyristor works as an inverter, generating an alternating current when a static direct-current voltage is applied. Whereas conventional thyristors consist of a series of diodes (their nonlinearity comes from interface effects at the p-n junctions), the present salt exhibits giant nonlinear resistance as a bulk phenomenon. We attribute the origin of this effect to the current-induced melting of insulating charge-order domains, an intrinsically non-equilibrium phenomenon in the sense that ordered domains are melted by a steady flow.

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Figure 1: Nonlinear resistance Vsample/Iex of a θ-(BEDT-TTF)2CsCo(SCN)4 crystal (sample B1) at 4.2 K.
Figure 2: Inverter (d.c.–a.c. conversion) phenomena in θ-(BEDT-TTF) 2 CsCo(SCN) 4 measured at 4.2 K.
Figure 3
Figure 4: Nonlinear resistance Vsample/Iex plotted as a function of 1/ T for various Iex.
Figure 5: Diffuse scattering intensities for θ -(BEDT-TTF) 2 CsZn(SCN) 4 with various external currents applied along the c -axis direction at 12 K.


  1. Streetman, B. G. Solid State Electronic Devices 2nd edn, Ch. 11 (Prentice-Hall, Englewood Cliffs, 1980)

    Google Scholar 

  2. Mori, H., Tanaka, S. & Mori, T. Systematic study of the electronic state in θ-type BEDT-TTF organic conductors by changing the electronic correlation. Phys. Rev. B 57, 12023–12029 (1998)

    Article  ADS  CAS  Google Scholar 

  3. Seo, H. Charge ordering in organic ET compounds. J. Phys. Soc. Jpn 69, 805–820 (2000)

    Article  ADS  CAS  Google Scholar 

  4. Clay, R. T., Mazumdar, S. & Campbell, D. K. Charge ordering in θ-(BEDT-TTF)2X materials. J. Phys. Soc. Jpn 71, 1816–1819 (2002)

    Article  ADS  CAS  Google Scholar 

  5. Nogami, Y. et al. Structural modulation in θ-(BEDT-TTF)2CsM′(SCN)4[M′ = Co, Zn]. Synth. Met. 103, 1911 (1999)

    Article  CAS  Google Scholar 

  6. Watanabe, M., Nogami, Y., Oshima, K., Mori, H. & Tanaka, S. Novel pressure-induced 2kF CDW state in organic low-dimensional compound θ-(BEDT-TTF)2CsCo(SCN)4 . J. Phys. Soc. Jpn 68, 2654–2663 (1999)

    Article  ADS  CAS  Google Scholar 

  7. Mori, T. Non-stripe charge order in the θ-phase organic conductors. J. Phys. Soc. Jpn 72, 1469–1475 (2003)

    Article  ADS  CAS  Google Scholar 

  8. Nishio, Y. et al. Specific heat and metal-insulator transition of (BEDT-TTF)2MZn(SCN)4 (M = Cs, Rb). Synth. Met. 103, 1905–1906 (1999)

    Article  Google Scholar 

  9. Takahashi, T. et al. Charge ordering in non-dimerized BEDT-TTF based organic conductors: 13C-NMR experiments. Phys. IV Fr. 12(Pr9), 201–204 (2002)

    Google Scholar 

  10. Inagaki, K., Terasaki, I., Mori, H. & Mori, T. Large dielectric constant and giant nonlinear conduction in the organic conductor θ-(BEDT-TTF)2CsZn(SCN)4 . J. Phys. Soc. Jpn 73, 3364–3369 (2004)

    Article  ADS  CAS  Google Scholar 

  11. Maeda, A., Notomi, M., Uchinokura, K. & Tanaka, S. Evidence for the existence of the inherent periodicity in the switched state at low temperatures in K0.3MoO3 . Phys. Rev. B 36, 7709–7711 (1987)

    Article  ADS  CAS  Google Scholar 

  12. Gunn, J. B. Microwave oscillations of current in III–V semiconductors. Solid State Commun. 1, 88–91 (1963)

    Article  ADS  Google Scholar 

  13. Gruner, G. Density Waves in Solids 56–57 (Addison-Wesley, Reading, Massachusetts, 1994)

    Google Scholar 

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We thank K. Inagaki for collaboration, and A. Maeda for technical advice for nonlinear-conduction and noise measurements. We also thank S. Tasaki, S. Kurihara, M. Abdel-Jawad, and N. E. Hussey for discussions. This work was partially supported by MEXT, the Grant-in-Aid for Scientific Research, and by the 21st Century COE Program at Waseda University. Author Contributions F.S. did the electrical measurement, I.T. did the project planning and analysis, H.M. and T.M. did the sample preparation and chemical characterization, and M.W., N.I., Y.N. and Y.N. did the diffraction in electric fields.

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Correspondence to I. Terasaki.

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Sawano, F., Terasaki, I., Mori, H. et al. An organic thyristor. Nature 437, 522–524 (2005).

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