Spintronics and Quantum Information Processing with 1D Ge/Si Nanowires

本研究的目标是实现基于半导体纳米线的新型电子器件，包括基于自旋的场效应晶体管和量子超导晶体管，并探索基于固态的量子信息处理方案。该方法是基于在化学合成的、分子大小的锗/硅纳米线中形成的干净的一维空穴气体系统。长平均自由程、可调应变和量子约束效应在空穴气体系统中提供了独特的潜力，包括长自旋弛豫长度和门可控自旋轨道耦合效应。将探讨自旋电注入半导体系统。基于耦合量子点中载流子自旋的量子比特也将被研究。最终量子位态的读出将通过使用射频单电子晶体管作为电荷传感器的自旋电荷转换方案来实现。这项研究，由于其独特的结合自旋电子学，量子信息处理，纳米结构的受控生长和技术上重要的第四组材料的利用，可能会对社会产生重大的广泛影响。这里开发的自旋电子学器件和量子比特将为社会提供新的计算和密码手段，并影响包括电气工程，物理和化学在内的许多领域。同时，在研究过程中获得的知识将有助于深入了解自旋动力学和量子力学的基本知识。更广泛的影响最后，本提案中描述的活动的研究部分将与本科生和研究生水平的教育以及旨在扩大所提议的研究影响的其他活动密切相关。

The objective of this research is to realize novel electronic devices based on semiconductor nanowires, including spin based field-effect transistors and quantum supercurrent transistors, and to explore solid-state based quantum information processing schemes. The approach is based on a clean one-dimensional hole gas system formed in chemically synthesized, molecular size germanium/silicon nanowires. The long mean free path, along with tunable strain and quantum confinement effects in the hole gas system offer unique potential including long spin relaxation length and gate controllable spin-orbit coupling effects. Electrical injection of spin into the semiconductor system will be explored. Qubits based on carrier spins in coupled quantum dots will also be studied. Read-out of the final qubit state will be implemented with a spin-charge conversion scheme using a radio-frequency single-electron transistor as the charge sensor.Intellectual MeritThis research, due to its unique combination of spintronics, quantum information processing, controlled growth of nanostructures, and utilization of technologically important group IV materials, is likely to have significant broad impact for society. The spintronics devices and qubits developed here will provide the society with new means of computation and cryptography, and affect numerous fields including electrical engineering, physics and chemistry. In the meantime, the knowledge gained during research will give insight into basic understanding of spin dynamics and quantum mechanics. Broader ImpactFinally, the research component of the activities described in this proposal will be closely tied to education at both the undergraduate and graduate student level, and other activities intended to broaden the impact of the proposed research.