| Budget Amount *help |
¥5,500,000 (Direct Cost: ¥5,500,000)
Fiscal Year 1999: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1998: ¥4,700,000 (Direct Cost: ¥4,700,000)
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| Research Abstract |
The purpose of this project is to make clear if quantum effect is relevant to dynamics of the density wave, especially sliding and related phenomena. Because it is generally expected that quantum effect is probable in the spin-density wave, in which the effective mass of condensed electrons is small, the nonlinear conduction and transient voltage oscillation in (TMTSF) ィイD22ィエD2AsFィイD26ィエD2, one of its typical materials. The conductivity measured at atmospheric pressure is stained by the irregular current path due to micro-cracks induced during cooling, samples were slightly pressurized. In thick crystals current flows in a non-uniform manner, it was decided to use thin samples with thickness presumably smaller than the phase correlation lenth were used. Samples with cross-sectional area less than 200 um2 were selected and used.
It was found that the sliding threshold electric field is about 100 V/m, one order of magnitude larger than that in thick crystals. It is approximately temperature independent contrary to thick ones. The pinning length estimated from the transient voltage oscillation frequency is in agreement with the wavelength of the spin-density wave; the sliding is uniform over its cross-section. It is concluded that, in order to make clear the significance of quantum effect, measurements should be repeated with thinner crystals and at lower temperature than those used in this project. It has been made clear that tecniques to hand such thinner crystals should be developed.
Conductivity of a new charge transfer organic salt, (TMDSA)X, was measured. While it became apparent that its conductivity is nonlinear at low temperature, its details are strongly sample dependent.
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