All-Electric Semiconductor Spin Valve

全电动半导体旋转阀

• 批准号: 1028423
• 负责人: Marc Cahay
• 金额: $ 34.49万
• 依托单位: University of Cincinnati Main Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-15 至 2013-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1028423&HistoricalAwards=false
• 关键词: Electric; Semiconductor; Spin; Valve

A concerted experimental and theoretical research program is proposed to develop an all-electric, lateral spin valve with a large (~ 30) On/Off conductance ratio. The device will be made from gallium arsenide and will not use any ferromagnetic electrodes or external magnetic field to flip the electron spin. It consists of two quantum point contacts in series separated by a short one-dimensional conduction channel of length smaller than the spin coherence length of gallium arsenide at the temperature of operation. Each quantum point contact acts as all-electric spin polarizer or detector and can provide or filter almost completely spin-polarized current. Non-equilibrium Green¡¦s function simulation of model devices indicate that spin valve devices based on gallium arsenide quantum point contacts on length scale of tens of nanometers, achievable with modern lithographic technology, can yield a large enough spin splitting to make feasible operation at ambient temperature with large On/Off conductance ratio.Intellectual meritThe creation, manipulation, and detection of spin-polarized currents by purely electrical means are challenging goals in semiconductor spintronics. Spin valves so far studied have used ferromagnetic electrodes or material embedded into device architecture for spin polarization and detection and an external magnetic field to flip the spin. Very recently, we have demonstrated that quantum point contact made from the semiconductor indium arsenide can be used to generate strongly spin polarized current by purely electrical means when its confining potential is made highly asymmetric by gate bias voltages. The spin valves based on gallium arsenide quantum point contacts we will develop in this project are unique in two respects. First, all-electric quantum point contacts will be used as spin polarizer and detector. Second, a one-dimensional transport channel is used that offers a number of advantages over two-dimensional channels used so far. Finally, because of the long (tens of micrometers) spin coherence length of gallium arsenide relative to that (tens of nanometers) of indium arsenide at room temperature, operation of the gallium arsenide spin valves at ambient temperature is feasible. If successful, this project will be ground-breaking. Broader ImpactsThe success of this project is expected to stimulate the development of all-electric, ultra high-speed, energy-efficient spin valve devices that can be used for high-speed digital information processing and eventually in solid-state quantum computation based on spin qubits. This project, if successful, will be a major milestone and a breakthrough in semiconductor spintronics. A goal of this project is to develop the first simulator based on non-equilibrium Green¡¦s function technique to model spin transport in nanoscale devices and make it available to the scientific community at large via the nanoHUB website. Both graduate and undergraduate students will participate in this research effort. This project will specifically engage undergraduate physics/engineering students of Xavier University and the University of Cincinnati to cutting edge physics research and advanced techniques not accessible in traditional undergraduate programs and courses.

提出了一个协调一致的实验和理论研究计划，以发展一个全电动，横向自旋阀与大（~ 30）开/关电导比。该装置将由砷化镓制成，不使用任何铁磁电极或外部磁场来翻转电子自旋。它由两个串联的量子点接触组成，它们被一个短的一维导电通道隔开，该通道的长度小于砷化镓在工作温度下的自旋相干长度。每个量子点接触充当全电自旋极化器或检测器，并且可以提供或过滤几乎完全自旋极化的电流。非平衡绿色…模型器件的β s函数模拟表明，利用现代光刻技术可以实现几十纳米尺度的砷化镓量子点接触自旋阀器件，其自旋分裂足够大，可以在室温下实现大的开/关电导比的工作。和通过纯电手段检测自旋极化电流是半导体自旋电子学中具有挑战性的目标。到目前为止，研究的自旋阀使用铁磁电极或嵌入到设备架构中的材料进行自旋极化和检测，并使用外部磁场来翻转自旋。最近，我们已经证明，由半导体砷化铟制成的量子点接触可以用来产生强自旋极化电流时，其限制电位是由栅极偏置电压高度不对称的纯电气手段。我们将在这个项目中开发的基于砷化镓量子点接触的自旋阀在两个方面是独一无二的。首先，全电量子点接触将被用作自旋极化器和探测器。其次，使用一维传输信道，其提供了许多优于迄今为止使用的二维信道的优点。 最后，由于室温下砷化镓的自旋相干长度相对于砷化铟的自旋相干长度（几十纳米）长（几十微米），所以砷化镓自旋阀在环境温度下的操作是可行的。如果成功的话，这个项目将是开创性的。更广泛的影响该项目的成功有望刺激全电动，超高速，节能的自旋阀器件的发展，可用于高速数字信息处理，并最终用于基于自旋量子位的固态量子计算。这个项目如果成功，将是半导体自旋电子学的一个重大里程碑和突破。该项目的目标之一是开发第一个基于非平衡绿色函数技术的模拟器，以模拟纳米器件中的自旋输运，并通过nanoHUB网站向科学界提供。 研究生和本科生都将参与这项研究工作。该项目将专门吸引泽维尔大学和辛辛那提大学的本科物理/工程专业的学生，以进行传统本科课程和课程无法获得的前沿物理研究和先进技术。