Mesoscopic phenomena in fine structures fabricated by nano-porous Alumina membranes

该研究项目的目标是在由纳米多孔氧化铝膜制造的独特纳米结构中发现在过去由半导体纳米技术制造的纳米结构中不可观察到的新的量子介观现象。成功实现了以下几个方面的工作：1.单纳米隧道结/高阻抗量子线阵列的库仑阻塞（CB）。我们将具有电子-电子相互作用的镍纳米线和具有局域化、电子波相位干涉效应的多壁碳纳米管连接到单个纳米隧道结上。成功地观察到了结构之间的不同CB。指出电子-电子相互作用引起的相位涨落能量和充电能量是Ni丝/单结系统的关键。相反，我们提出了一个问题，“在高阻抗外部环境中的能量耗散实际上是产生单结系统中的CB所必需的吗？“，在MWNT/单结系统中。这是因为产生CB的定位是一种弹性现象。2.成功地将MWNTs制备成氧化铝膜。我们发现，电子波在多壁碳纳米管的相位干涉是非常敏感的杂质的顶端的多壁碳纳米管的体积比只有5%。首次发现重质量杂质（Au、Pt）中的自旋轨道相互作用将MWNT中的弱局域化改变为反局域化。3.成功观察到Ni纳米线中起源于磁畴壁宏观量子隧穿（MQT）的突然磁阻（MR）跳跃。通过详细的测量。首次研究了MQT与弱局域化的相关性。4.测量了Ni量子线之间的磁共振振荡以及磁共振系数与Ni量子线直径的关系。

The goal of this research project was to find novel quantum-mesoscopic phenomena, unobservable in the past nanostrutures fabricated by semiconductor nano-technologies, in unique nanostrucures fabricated by nano-porous Alumina membranes. The following things were successfully observed.1.Coulomb blockade (CB) in an array of single nano-tunnel junctions/high-impedance quantum-wires. We connected Ni-nanowires with electron-electron interaction following Altshuler's theory and multi-walled carbon nanotubes (MWNT) with localization, phase interference effect of electron waves, to single nano-tunnel junctions. CB, different between the structures, was successfully observed. We pointed out that phase fluctuation energy caused by electron-electron interaction and charging energy were the key for the Ni-wires/single junctions system. In contrast, we provided a question, "Is energy dissipation in high-impedance external environment actually indispensable to yield CB in single junction systems? ", in MWNTs/single junction systems. It was because localization, yielding CB, was an elastic phenomenon.2.Successful fabrication of MWNTs into Alumina membranes. We found that phase interference of electron waves in the MWNTs was very sensitive to the impurities on the top end of the MWNTs with only 5% in volume ratio. It was firstly found that spin-orbit interaction in heavy-mass impurities (Au, Pt) changed the weak localization in MWNTs to the anti localization.3.Successful observation of abrupt magnetoresistnce (MR) jumps originated from macroscopic quantum tunneling (MQT) of magnetic domain walls, in Ni-nanowires., by detailed measurements. Correlation of the MQT with weak localization was also firstly investigated.4.MR oscillation measured among the Ni-quantum wires and dependence of coecivity on Ni-wire diameter.