Collaborative Research: Coherent Spin Control in Microfabricated Semiconductor Geometries

在过去的十年中，“半导体自旋电子学”的发展取得了迅速的进展，这是一个研究领域，其广泛的目标是利用电子自旋来实现具有半经典和量子特征的定性新半导体器件功能。该合作项目旨在利用半导体自旋电子学的最新基本发现（如自旋霍尔效应和微谐振器中自旋相干性的增强）来系统地控制微图案半导体器件中的相干自旋现象。我们将发展自旋霍尔效应的静态和动态电测量，并寻求提高这一现象的幅度的途径。我们还打算继续研究耦合光学微腔中自旋的纠缠和相干操纵，最终目标是相干控制单个自旋。最后，我们将在顺磁性和铁磁性半导体异质结构中进行利用界面交换相互作用进行相干自旋控制的实验。研究方法包括空间分辨飞秒光谱学、变温磁输运、直接磁化、扫描探针显微镜、分子束外延生长和亚微米制造技术。该项目是两位主要研究人员的综合努力，强调凝聚态物理的基础发现，但也有对未来信息技术可能具有潜在重要性的现象的清晰关注。该项目将复杂的测量技术与先进的材料工程相结合，从而为本科生和研究生提供基础物理和材料科学方面的前沿培训。当代信息技术依靠电子的电荷进行计算（逻辑），依靠被称为电子自旋的磁性来进行永久存储。过去十年见证了“半导体自旋电子学”的快速发展，这一研究领域的广泛目标是将这些传统上分离的功能集成在一起。这一建议是针对半导体自旋电子学的基本前沿，在那里我们寻求控制电子自旋的行为在微观图案半导体芯片。通过利用狭义相对论在固态晶体中的结果，我们将开发探测和利用“自旋霍尔效应”的电子手段，这是一个世纪前发现的经典霍尔效应的当代自旋模拟。增强我们对自旋霍尔效应的基本理解，可能使我们能够设想出新型自旋电子器件，这些器件利用量子物理的非直觉定律来实现新型逻辑，而不需要磁场或磁性材料。我们还打算开发实验，探索精细调谐的“微谐振器”中自旋的量子控制，微米大小的“盒子”可以捕获光，从而增强其与电子自旋的相互作用。我们的最终目标是在这样的盒子中对单个电子自旋进行量子力学控制，从而在单个设备中实现计算和光通信。最后，我们将开发实验，利用磁性离子和流动电子在精心设计的界面之间的相互作用。该项目是两位主要研究人员的综合努力，强调基础发现，但对可能对未来信息技术具有潜在重要性的现象有清晰的看法。该项目将复杂的测量技术与先进的材料工程相结合，从而为本科生和研究生提供基础物理和材料科学方面的前沿培训。

Technical The past decade has witnessed rapid advances in the development of "semiconductor spintronics," an area of research that broadly aims to exploit electron spin for qualitatively new semiconductor device functionality of both semi-classical and quantum character. This collaborative project is aimed at harnessing recent fundamental discoveries in semiconductor spintronics (such as the spin Hall effect and the enhancement of spin coherence in micro-resonators) for the systematic control of coherent spin phenomena in micro-patterned semiconductor devices. We will develop static and dynamical electrical measurements of the spin Hall effect as well seek pathways for enhancing the magnitude of this phenomenon. We also intend to pursue investigations that explore the entanglement and coherent manipulation of spins in coupled optical microcavities, with the ultimate goal of coherently controlling a single spin. Finally, we will conduct experiments that exploit the exchange interaction across interfaces for coherent spin control in both paramagnetic and ferromagnetic semiconductor heterostructures. Methods of investigation include spatially-resolved femtosecond optical spectroscopies, variable-temperature magnetotransport, direct magnetization, scanning probe microscopies, molecular beam epitaxial growth, and submicron fabrication techniques. The project is an integrated effort between the two principal investigators, emphasizing fundamental discovery in condensed matter physics, but with a clear eye on phenomena that could be of potential importance for future information technologies. The project combines sophisticated measurement techniques with advanced materials engineering, thus providing cutting edge training in both fundamental physics and materials science for undergraduate and graduate students. Non-technical Contemporary information technology relies on the charge of electrons for computation (logic) and the magnetic properties called spin of electrons for permanent storage. The past decade has witnessed rapid advances in the development of "semiconductor spintronics," an area of research that broadly aims to integrate these traditionally separate functionalities. This proposal is aimed at the fundamental frontiers of semiconductor spintronics, where we seek to control the behavior of electron spin in microscopically patterned semiconductor chips. By exploiting the consequences of special relativity in solid state crystals, we will develop electrical means of probing and harnessing the "spin Hall effect," a contemporary spin analog of the classical Hall effect discovered over a century ago. Enhancing our fundamental understanding of the spin Hall effect may allow us to envision new classes of spintronic devices that exploit the non-intuitive laws of quantum physics for new types of logic without the need for magnetic fields or magnetic materials. We also intend to develop experiments that explore the quantum control of spins in finely tuned "micro-resonators," micron sized "boxes" that trap light and thus enhance its interaction with the spin of electrons. Our ultimate goal is the quantum mechanical control of a single electron spin in such boxes, enabling both computation and optical communication in a single device. Finally, we will develop experiments that exploit the interaction between magnetic ions and itinerant electrons across exquisitely designed interfaces. The project is an integrated effort between the two principal investigators, emphasizing fundamental discovery but with a clear eye on phenomena that could be of potential importance for future information technologies. The project combines sophisticated measurement techniques with advanced materials engineering, thus providing cutting edge training in both fundamental physics and materials science for undergraduate and graduate students.