Coherent spin transport in III-V semiconductors

III-V族半导体中的相干自旋输运

• 批准号: 64100186
• 负责人: Dr. Bernd Beschoten
• 金额: --
• 依托单位: II. Physikalisches Institut A - Physik der kondensierten Materie
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2008
• 资助国家: 德国
• 起止时间: 2007-12-31 至 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/64100186?language=en
• 关键词: Coherent; spin; transport; III; semiconductors

We have focused on developing electrical methods for generating and manipulating coherent spin states in III-V semiconductor structures without magnetic electrodes. We propose for the next funding period to combine these methods, which would allow to generate and to manipulate coherent spins all-electrically by two time-delayed electric field pulses. Furthermore, we propose a scheme for spin dependent coherent electrical detection. While in this experiment spins shall be generated by optical orientation, we suggest using timeresolved spin photo-voltage measurements as an electrical probe for coherent spin currents. The controlled optical excitation of electron spins in perpendicular directions shall furthermore be used to study spin relaxation anisotropy. In a second focus, we will extend our spin transport studies to semiconductor nanowires. We propose two experiments of different complexity. Firstly, we will fabricate non-local spin-valves for spin injection and detection using ferromagnetic electrodes and MgO as injection barrier. Conventional magneto-transport including electrical Hanlé measurements shall be used to determine spin relaxation times and lengths. Secondly, we propose to optically generate spin currents in the nanowires. The spin currents shall be probed either directly by photo-voltages or by magnetoresistive changes when using ferromagnetic electrodes as spin detectors.

我们专注于开发用于在没有磁性电极的III-V族半导体结构中产生和操纵相干自旋态的电学方法。我们建议在下一个资助期内将这些方法联合收割机结合起来，这将允许通过两个时间延迟的电场脉冲全电地产生和操纵相干自旋。此外，我们还提出了一种自旋相关相干电探测方案。虽然在这个实验中自旋将产生的光学取向，我们建议使用时间分辨的自旋光电压测量作为电探针的相干自旋电流。此外，垂直方向上电子自旋的受控光激发将用于研究自旋弛豫各向异性。在第二个重点，我们将我们的自旋输运研究半导体纳米线。我们提出了两个不同复杂性的实验。首先，我们将利用铁磁电极和氧化镁作为注入阻挡层来制作用于自旋注入和探测的非局域自旋阀。应使用常规磁输运（包括电Hanlé测量）来确定自旋弛豫时间和长度。其次，我们提出在纳米线中光学产生自旋电流。当使用铁磁电极作为自旋探测器时，应直接通过光电压或磁阻变化探测自旋电流。