Suda Ryutaro, Yagi Mamiko, Watanabe Takato, Shirakashi Jun-Ichi
Department of Electrical and Electronic Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan.
J Nanosci Nanotechnol. 2013 Feb;13(2):883-7. doi: 10.1166/jnn.2013.6072.
We propose a new fabrication scheme of quantum point contacts (QPCs) composed of nanogaps at room temperature. This scheme is based on electromigration induced by a field emission current, which is so-called "activation." By applying the activation to ferromagnetic Ni nanogaps with sub-10 nm separation, QPCs can be easily obtained at room temperature. The conductance changed in quantized steps of 0.5G0 (G0 = 2e2/h) at the final stage of activation with a preset current Is of 0.5 mA. Then, the conductance during the activation was varied from 2G0 to 9.5G0 by increasing the preset current Is from 0.5 mA to 1.5 mA. Furthermore, after performing the activation with the preset current Is of 1.5 mA, the QPC device formed by the activation exhibited magnetoresistance (MR) ratio of approximately 1.5%. These results indicate that few-atom Ni contacts are achieved using Ni nanogaps controlled by the activation with precisely tuned preset current.
我们提出了一种在室温下由纳米间隙组成的量子点接触（QPC）的新制造方案。该方案基于场发射电流诱导的电迁移，即所谓的“激活”。通过将激活应用于间距小于10 nm的铁磁镍纳米间隙，在室温下可以轻松获得QPC。在激活的最后阶段，当预设电流Is为0.5 mA时，电导以0.5G0（G0 = 2e2/h）的量子化步长变化。然后，通过将预设电流Is从0.5 mA增加到1.5 mA，激活过程中的电导从2G0变化到9.5G0。此外，在用1.5 mA的预设电流Is进行激活后，由激活形成的QPC器件表现出约1.5%的磁阻（MR）比率。这些结果表明，通过精确调谐预设电流的激活来控制镍纳米间隙，可以实现由少数原子组成的镍接触。
