CAREER: Nanoscale Ballistic Spin Transport in Semiconductors

****非技术摘要****与电荷一起，电子具有称为自旋的量子力学性质。一种基于电子自旋的未来技术被命名为自旋电子学。自旋电子器件有望比目前的电子器件更强大、更便宜、更轻、消耗更少的能量。为了发展这种基于自旋的技术，有必要研究半导体中自旋的运动。这个学院早期职业奖支持一个研究半导体纳米级自旋输运的项目。到目前为止，大多数研究都集中在微米甚至更大长度尺度上的自旋输运。为了将自旋电子学与纳米技术相结合，理解和控制半导体中纳米尺度的自旋输运是至关重要的。这种运输将在很短的时间内进行。该项目将使用新型激光技术解决这一关键问题，该技术能够检测快至70飞秒的事件和小至百分之一纳米的自旋运动。砷化镓及其纳米结构将用于研究无碰撞自旋输运（称为弹道自旋输运）的几个关键方面。该项目将提高我们对半导体自旋动力学的认识，并为纳米级自旋电子学提供全面的信息。这个项目的教育部分与研究工作很好地结合在一起。将开设一门关于激光原理和技术的新课程。尖端研究将涉及研究生和本科生，以及高中教师。关于在非常短的时间尺度上发生的事情的外展项目以及关于材料基本过程的项目也将根据研究主题进行开发。****技术摘要****该学院早期职业奖支持半导体体、量子阱和量子线中纳米级弹道自旋输运的实验研究。自旋输运是自旋电子器件中的一个基本过程。到目前为止，大多数研究都集中在大尺度的输运上，其中输运主要是漂移-扩散过程。由于集成电路上电子器件的尺寸已经缩小到60纳米，这与电子的平均自由程相当甚至更小，因此有必要在纳米尺度上理解和控制弹道自旋输运。在这个项目中，半导体中的纳米级自旋输运将通过使用超快激光技术进行研究，该技术的时间分辨率为70飞秒，并且能够检测到小到10皮米的运动。通过跟踪自旋在真实空间和实时中的位置，可以直接观察和研究纳米尺度的弹道自旋输运。将研究弹道自旋输运的几个关键方面。所提出的研究将为纳米自旋电子学提供全面的信息，并揭示涉及弹道自旋输运的丰富物理。这个项目的教育部分与研究工作很好地结合在一起。将开设一门关于激光原理和技术的新课程。尖端研究将涉及研究生和本科生，以及高中教师。此外，还将根据研究课题制定外展项目。

****NON-TECHNICAL ABSTRACT****Along with charge, electrons have a quantum mechanical property known as ?spin.? A future technology that would be based on the spin of electrons has been named ?spintronics.? Spintronic devices are expected to be more powerful, less expensive, lighter, and consume less energy than the present electronic devices. To develop this spin-based technology, it is necessary to study movement of spin in semiconductors. This Faculty Early Career Award supports a project that will investigate nanometer-scale spin transport in semiconductors. So far, most studies have focused on spin transport at the micrometer or even larger length scales. To integrate spintronics with nanotechnology, it is crucial to understand and control nanometer-scale spin transport in semiconductors. Such transport will take place on very short timescales. This project will address this key issue using novel laser techniques that are capable of detecting events as fast as 70 femtoseconds and spin movements as small as one hundredth of nanometer. Gallium Arsenide and its nanostructures will be used to study several key aspects of the collision-free spin transport (known as ballistic spin transport). This project will advance our knowledge of spin dynamics in semiconductors, and provide comprehensive information for nanoscale spintronics. The education component of this project is well integrated with the research efforts. A new course on laser principles and techniques will be developed. The cutting edge research will involve graduate and undergraduate students, as well as high-school teachers. Outreach projects concerning what happens at very short time scales as well as projects concerning fundamental processes in materials will also be developed based on the research topics.****TECHNICAL ABSTRACT****This Faculty Early Career Award supports experimental investigations of nanoscale ballistic spin transport in semiconductor bulk, quantum wells and quantum wires. Spin transport is a fundamental process in spintronic devices. So far, most studies have focused on transport on large length scales where the transport is dominated by the drift-diffusion processes. Since the size of electronic devices on integrated circuits has been reduced to 60 nm, which is comparable to or even smaller than the mean free path of electrons, it is necessary to understand and control ballistic spin transport on the nanoscale. In this project, nanoscale spin transport in semiconductors will be studied by using ultrafast laser techniques with a temporal resolution of 70 femtoseconds and a capability of detecting movements as small as 10 picometers. Nanoscale ballistic spin transport will be directly observed and studied by tracking the position of spins in real space and real time. Several key aspects of ballistic spin transport will be studied. The proposed research will provide comprehensive information for nano-spintronics and reveal rich physics involved in ballistic spin transport. The education component of this project is well integrated with the research efforts. A new course on laser principles and techniques will be developed. The cutting edge research will involve graduate and undergraduate students, as well as high-school teachers. Outreach projects will also be developed based on the research topics.