Long Y Z, Yin Z H, Chen Z J, Jin A Z, Gu C Z, Zhang H T, Chen X H
College of Physics Science, Qingdao University, Qingdao 266071, People's Republic of China.
Nanotechnology. 2008 May 28;19(21):215708. doi: 10.1088/0957-4484/19/21/215708. Epub 2008 Apr 23.
The current-voltage (I-V) characteristics and electrical resistivity of isolated potassium manganese oxide (K(0.27)MnO(2)·0.5H(2)O) nanowires prepared by a simple hydrothermal method were investigated over a wide temperature range from 300 to 4 K. With lowering temperature, a transition from linear to nonlinear I-V curves was observed around 50 K, and a clear zero bias anomaly (i.e., Coulomb gap-like structure) appeared on the differential conductance (dI/dV) curves, possibly due to enhanced electron-electron interaction at low temperatures. The temperature dependence of resistivity, [Formula: see text], follows the Efros-Shklovskii (ES) law, as expected in the presence of a Coulomb gap. Here we note that both the ES law and Coulomb blockade can in principle lead to a reduced zero bias conductance at low temperatures; in this study we cannot exclude the possibility of Coulomb-blockade transport in the measured nanowires, especially in the low-temperature range. It is still an open question how to pin down the origin of the observed reduction to a Coulomb gap (ES law) or Coulomb blockade.
通过简单水热法制备的孤立钾锰氧化物（K(0.27)MnO(2)·0.5H(2)O）纳米线的电流-电压（I-V）特性和电阻率在300至4 K的宽温度范围内进行了研究。随着温度降低，在50 K左右观察到I-V曲线从线性向非线性转变，并且在微分电导（dI/dV）曲线上出现了明显的零偏置异常（即类似库仑能隙的结构），这可能是由于低温下电子-电子相互作用增强所致。电阻率的温度依赖性，[公式：见正文]，遵循埃弗罗斯-什克洛夫斯基（ES）定律，这在存在库仑能隙的情况下是预期的。在此我们注意到，ES定律和库仑阻塞原则上都可以导致低温下零偏置电导降低；在本研究中，我们不能排除在所测量的纳米线中存在库仑阻塞输运的可能性，特别是在低温范围内。如何确定所观察到的降低的起源是库仑能隙（ES定律）还是库仑阻塞，这仍然是一个悬而未决的问题。
