Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.
ACS Nano. 2011 Aug 23;5(8):6365-73. doi: 10.1021/nn201482y. Epub 2011 Jul 22.
Control of electron spins in individual magnetically doped semiconductor nanostructures has considerable potential for quantum information processing and storage. The manipulations of dilute magnetic interactions have largely been restricted to low temperatures, limiting their potential technological applications. Among the systems predicted to be ferromagnetic above room temperature, Mn-doped GaN has attracted particular attention, due to its attractive optical and electrical properties. However, the experimental data have been inconsistent, and the origin of the magnetic interactions remains unclear. Furthermore, there has been no demonstration of tuning the dopant exchange interactions within a single nanostructure, which is necessary for the design of nanoscale spin-electronic (spintronic) devices. Here we directly show for the first time intrinsic magnetization of manganese dopants in individual gallium nitride nanowires (NWs) at room temperature. Using high-resolution circularly polarized X-ray microscopy imaging, we demonstrate the dependence of the manganese exchange interactions on the NW orientation with respect to the external magnetic field. The crystalline anisotropy allows for the control of dilute magnetization in a single NW and the application of bottom-up approaches, such as in situ nanowire growth control or targeted positioning of individual NWs, for the design of networks for quantum information technologies.
在单个磁性掺杂半导体纳米结构中控制电子自旋对于量子信息处理和存储具有相当大的潜力。稀磁相互作用的操纵在很大程度上受到低温的限制，限制了它们的潜在技术应用。在预测的室温以上铁磁体系统中，由于其吸引人的光学和电学性质，Mn 掺杂 GaN 引起了特别关注。然而，实验数据一直不一致，磁相互作用的起源仍不清楚。此外，还没有在单个纳米结构中调整掺杂剂交换相互作用的演示，这对于设计纳米级自旋电子（spintronic）器件是必要的。在这里，我们首次直接在室温下显示了单个氮化镓纳米线（NW）中锰掺杂剂的本征磁化强度。使用高分辨率圆偏振 X 射线显微镜成像，我们证明了 Mn 交换相互作用对 NW 相对于外磁场的方向的依赖性。晶各向异性允许在单个 NW 中控制稀磁，并且可以应用自下而上的方法，例如原位纳米线生长控制或单个 NW 的靶向定位，用于设计量子信息技术网络。
