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QUANTUM EFFECT IN DENSITY WAVE SLIDING

密度波滑动中的量子效应

基本信息

批准号：
10440084
负责人：
SAMBONGI Takashi
金额：
$ 3.52万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10440084/
关键词：
quantum effect density wave sliding スピン密度波非線型伝導サイズ効果

项目摘要

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.

这个项目的目的是弄清楚量子效应是否与密度波的动力学有关，特别是滑动和相关现象。由于一般认为凝聚态电子的有效质量很小的自旋密度波中可能存在量子效应，因此，（TMTSF）D22的典型材料之一的（TMTSF）D22 AsF 26 AsF 26 AsF 26 D26中的非线性导电和瞬态电压振荡现象十分明显。在大气压下测量的电导率被不规则的电流路径染色，这是由于在冷却过程中诱导的微裂纹，样品被轻微加压。在厚晶体中，电流以不均匀的方式流动，决定使用厚度大概小于相位相关长度的薄样品。选用截面积小于200 μ m ~ 2的样品，发现其滑动阈值电场约为100 V/m，比厚晶体中的大一个数量级。与厚膜相反，它近似与温度无关。从瞬态电压振荡频率估计的钉扎长度是在协议的自旋密度波的波长，滑动是均匀的在其横截面上。得出的结论是，为了明确量子效应的意义，测量应重复使用更薄的晶体和在更低的温度比在这个项目中使用的。测量了一种新的电荷转移有机盐（TMDSA）X的电导率。虽然很明显，它的电导率在低温下是非线性的，但其细节与样品密切相关。