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The Aharonov-Bohm effect of the charge-density wave in ring-shaped crystals of quasi-one dimensional conductors

准一维导体环形晶体中电荷密度波的阿哈罗诺夫-玻姆效应

基本信息

批准号：
14540347
负责人：
OKAJIMA Yoshitoshi
金额：
$ 2.24万
依托单位：
Asahikawa National College of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

A tube-shaped single crystal was taken out from a batch of the quasi-one-dimensional conductor NbSe3. The crystal was sliced into several disks by focused ion beam (FIB) milling. Tube-shaped single crystals have a hole along the center axis. The sliced disks also have a hole at the center of them. The part of the disk away from the hole was milled using FIB, and the part near the hole was remained. We have successfully synthesized a ring sample of NbSe3 with a diameter of 〜5μm. The electrical contacts, were taken to the contact pads of the ring sample by evaporating indium. Measurements of resistance were performed by the four-probe method.Temperature dependence of resistance of the ring sample has been qualitatively the same as that of the whisker-shaped single crystals. Therefore, they are certain that the ring sample is the single crystal of NbSe3, that the charge-density-wave (CDW) transitions take place at the two transition temperatures, and that no damage is induced into the rin … More g sample through the FIB milling. The nonlinear conduction by the CDW sliding has been observed at several temperatures from 41K to 55K in the low-temperature CDW state. The ring sample synthesized in this study is suitable for studying whether the Aharonov-Bohm (AB) effect can be observed in the nonlinear conduction by the CDW sliding.In the measurements of magnetoresistance, the magnetic field was applied normal to the ring sample and the resistance was measured with changing strength of the magnetic field. The total current through the ring sample was kept constant. The resistance as a function of field strength seemed to show a periodic modulation. However, the modulation with the same amplitude was observed under the constant magnetic fields and constant currents. This fact means that the noise is large compared to the modulation by the magnetic field. Therefore, the periodic modulation of the magnetoresistnce has not been observed.It is not clarified whether the AB effect can be observed in the nonlinear conduction by the CDW sliding. It is needed that the signal-to-noise ratio is improved. Less

从一批准一维导体NbSe3中提取出管状单晶。通过聚焦离子束(FIB)球磨将晶体切成几个圆盘。管状单晶在中心轴上有一个孔。切片的圆盘的中心也有一个洞。盘片远离孔的部分用FIB铣削，而靠近孔的部分保留下来。我们成功地合成了直径约5μm的NbSe_3环形样品，通过蒸发铟将电触点带到环形样品的触头垫上。用四探针法进行了电阻测量，环形样品的电阻随温度的变化与晶须状单晶的电阻随温度的关系基本一致。因此，他们确定环形样品是NbSe3的单晶，电荷-密度-波(Cdw)相变发生在两个相变温度，并且不会对Rin-…造成损伤。更多的g样品通过FIB球磨。在低温CDW状态下，在41K到55K的几个温度范围内，观察到了CDW滑动的非线性导电。本文合成的环形样品适合于研究在CDW滑动的非线性导电过程中是否会观察到Aharonov-Bohm(AB)效应。在磁阻测量中，对环形样品施加垂直磁场，并随磁场强度的变化测量电阻。通过环形样品的总电流保持不变。作为场强函数的电阻似乎表现出周期性的调制。而在恒定磁场和恒流作用下，观察到了相同幅度的调制。这一事实意味着，与磁场的调制相比，噪声很大。因此，没有观察到磁阻的周期性调制，也不清楚在CDW滑动的非线性电导中是否会观察到AB效应。需要提高信噪比。较少