Magnetic Interactions in Mesoscopic Transport Studied by Millikelvin Scanning Probe Microscopy

Nunes扫描探针显微技术将应用于毫开尔文温度下量子输运中的磁相互作用研究。带有沉积磁性杂质的力显微镜尖端将用于在介观样品的已知位置放置已知类型的缺陷。这些人为引入的缺陷对自旋散射的影响将通过电导波动和窄线和环中的Aharonov-Bohm振荡来研究。这些实验将深入了解小型器件中的非弹性散射过程，并为通用电导波动理论提供灵敏的测试。探测和操纵纳米线和器件中缺陷的能力最终将允许在单个缺陷水平上研究量子输运的无序性。这个研究项目将把快速发展的扫描探针显微镜技术应用到纳米级电子器件缺陷的研究和处理中。过去，电测量只对器件的平均特性敏感，而不是对构成器件平均性能的单个缺陷敏感。扫描探针显微镜提供空间分辨的局部信息的能力，将使我们能够透过一般性质看到原子尺度上的基本行为。这一信息将提供任何其他方法都无法获得的新的物理见解——这些见解将用于预测和理解未来的纳米电子学，在纳米电子学中，原子尺度的无序将不可避免地影响名义上“相同”的设备的行为。＊＊＊

w:\awards\awards96\*.doc 9623847 Nunes Scanning probe microscopy techniques will be applied to the study of magnetic interactions in quantum transport at milliKelvin temperatures. Force microscope tips with deposited magnetic impurities will be used to place defects of a known type at known positions in a mesoscopic sample. The effect of spin scattering from these artificially introduced defects will be studied via conductance fluctuations and Aharonov-Bohm oscillations in narrow wires and rings. These experiments will provide insight into inelastic scattering processes in small devices, and offer sensitive tests of universal conductance fluctuation theory. The ability to probe and manipulate the defects in nanoscale wires and devices will ultimately allow the investigation of disorder in quantum transport at the single defect level. %%% This research program will apply techniques from the rapidly growing field of scanning probe microscopy to the study and manipulation of defects in nanoscale electronic devices. In the past, electrical measurements have only been sensitive to the average properties of a device, rather than to the individual defects out of which the average behavior is built up. The ability of scanned probe microscopes to provide spatially resolved, local information will allow us to look beneath the general properties to the underlying behavior on the atomic scale. This information will provide new physical insights unobtainable by any other means---insights which will be required for predicting and understanding the nano-electronics of the future in which the atomic-scale disorder will inevitably influence the behavior of nominally "identical" devices. ***