Toward Spin- and Valleytronic Devices

自旋电子学和最近出现的valley tronics是固态科学和工程中的新兴领域，它们利用载流子的自旋/谷自由度来实现依赖于自旋/谷电流的产生、操作和检测的新型电子设备。这种操纵预计将影响量子计算领域，因为自旋/山谷是在量子计算机中注册信息量子比特的候选对象。本文提出的项目的重点是研究层状半导体结构中清洁载体系统中的弹道传输。其目的是展示和描述一些电子设备，如自旋干扰装置、自旋过滤器和山谷过滤器，它们的运行依赖于自旋和/或山谷自由度的操纵。该项目包含一个全面的教育部分，包括研究生和本科生培训和课程开发。外展活动包括为新泽西州学校的K-12学生、公共图书馆和普林斯顿大学的教师培训项目开发演示工具包。拟议项目的主要目标是展示和描述一些电子设备的特性，这些设备的运行依赖于自转和/或山谷自由度的操纵。其中包括自旋干涉装置、自旋滤光器和谷滤光器。这种器件将主要基于两种不同的载流子系统：(1)具有强的可调的自旋-轨道相互作用的GaAs量子阱中的二维空穴系统；(2)AlAs量子阱中的二维电子系统，其中电子占据可调密度的导带谷，并且具有大的朗德有效g因子，因此它们很容易被自旋极化。这些项目将涉及使用现代晶体生长和光刻技术制造各种设备，以及运输测量。这些项目将有助于从根本上理解半导体结构中的弹道传输。这些知识对于自旋电子学和/或电子谷电子学和量子计算等新兴领域的进步至关重要。

Spintronics and, more recently, valleytronics, are emerging areas in solid state science and engineering that utilizes carriers' spin/valley degrees of freedom to realize novel electronic devices that rely on the creation, manipulation, and detection of spin/valley currents. Such manipulation is expected to impact the field of quantum computing, as spin/valley are candidates for registering the quantum bit of information in quantum computers. The focus of the projects proposed here is to study ballistic transport in clean carrier systems in layered semiconductor structures. The goal is to demonstrate and characterize a number of electronic devices such as spin-interference device, spin-filter, and valley-filter, whose operation relies on the manipulation of spin and/or valley degrees of freedom. The project incorporates a comprehensive educational component, including graduate and undergraduate students training and curriculum development. Outreach activities involve developing demonstration kits for K-12 students in New Jersey schools, for public libraries and for teachers training programs at Princeton University. The main goal of the proposed projects is to demonstrate and characterize a number of electronic devices whose operation relies on the manipulation of spin and/or valley degrees of freedom. These include a spin-interference device, a spin-filter, and a valley-filter. The devices will be based mainly on two different carrier systems: (1) two-dimensional hole system in GaAs quantum wells which possesses a strong and tunable spin-orbit interaction, and (2) 2D electron system in AlAs quantum wells where the electrons occupy conduction band valleys with tunable densities, and also have a large Lande effective g-factor so that they can be easily spin-polarized. The projects will involve fabrication of various devices using modern crystal growth and lithography techniques, and transport measurements. The projects will contribute to the fundamental understanding of the ballistic transport in semiconductor structures. Such knowledge is essential for advancements in the emerging fields of spintronics and/or valleytronics and quantum computing.