Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Nano Lett. 2013 Feb 13;13(2):430-5. doi: 10.1021/nl303667v. Epub 2013 Jan 22.
We demonstrate all-electrical spin injection, transport, and detection in heavily n-type-doped Si nanowires using ferromagnetic Co/Al(2)O(3) tunnel barrier contacts. Analysis of both local and nonlocal spin valve signals at 4 K on the same nanowire device using a standard spin-transport model suggests that high spin injection efficiency (up to ~30%) and long spin diffusion lengths (up to ~6 μm) are achieved. These values exceed those reported for spin transport devices based on comparably doped bulk Si. The spin valve signals are found to be strongly bias and temperature dependent and can invert sign with changes in the dc bias current. The influence of the nanowire morphology on field-dependent switching of the contacts is also discussed. Owing to their nanoscale geometry, ~5 orders of magnitude less current is required to achieve nonlocal spin valve voltages comparable to those attained in planar microscale spin transport devices, suggesting lower power consumption and the potential for applications of Si nanowires in nanospintronics.
我们在重掺杂 n 型硅纳米线中使用铁磁 Co/Al2O3 隧道势垒接触，演示了全电自旋注入、输运和检测。在相同的纳米线器件上，使用标准的自旋输运模型，对 4 K 下的局域和非局域自旋阀信号进行分析，表明实现了高自旋注入效率（高达约 30%）和长自旋扩散长度（高达约 6 μm）。这些值超过了基于类似掺杂体硅的自旋输运器件的报道。发现自旋阀信号强烈依赖于偏压和温度，并且随着直流偏置电流的变化可以反转符号。还讨论了纳米线形态对接触场相关开关的影响。由于其纳米级几何形状，与平面微尺度自旋输运器件中获得的非局域自旋阀电压相比，仅需几数量级的电流就可实现，这表明更低的功耗以及硅纳米线在纳米自旋电子学中的应用潜力。
