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Physics and applications of zero-magnetic-field spin splitting in semiconductor nano-structures

半导体纳米结构零磁场自旋分裂的物理及应用

基本信息

批准号：
15540304
负责人：
TSUCHIYA Takuma
金额：
$ 2.24万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15540304/
关键词：
spin precession qauantum wells spin coherence length Dresselhaus field Rashba field spin-FET nuclear spin compound semiconductors InAs スピン分裂量子井戸構造 Si Ge GaAs 強統合近似

项目摘要

In this project, we have investigated electron spin-precession spatial spin-coherence s in (001) quantum wells. Effects of nuclear spins on the spin precession have also been investigated.Results of Monte Carlo simulation, it has been clarified that shape of electrodes is important for sufficient spin coherence length. When the Rashba effective magnetic field is much larger than the Dresselhaus one, circular or Corbino electrodes are quite effective, because the effective field is perpendicular to the electron wave vector and the strength in proportional the length of it. On the other hand, when the Rashba and the Dresselhaus field are comparable, usual parallel electrodes are appropriate, but the electric current should along (110) or equivalent direction. Using these types of electrodes, we can get spin coherence length sufficient for device applicationsEffects of nuclear spin-polarization induced by electron spin-polarization is passively affects the electron spin-precession. We have investigated this effect also by Monte Carlo simulation. Nuclear spins are polarized in few seconds and induces magnetic field sufficient to affects the electron spin-precession. This induced field degrades strongly the electron spin-polarization. Thus, it is important for device application to develop some method to overcome this problem.

本项目研究了（001）量子威尔斯阱中电子自旋旋进的空间自旋相干性。研究了原子核自旋对自旋进动的影响，通过Monte Carlo模拟，阐明了电极的形状对自旋相干长度的重要性。当Rashba有效磁场远大于Dresselhaus磁场时，圆形或Corbino电极是很有效的，因为有效磁场垂直于电子波矢，其强度与其长度成正比;另一方面，当Rashba和Dresselhaus磁场相当时，通常的平行电极是合适的，但电流应沿沿着（110）或等效方向。电子自旋极化引起的核自旋极化效应是被动地影响电子的自旋进动。我们也通过Monte Carlo模拟研究了这种效应。核自旋在几秒钟内被极化，并产生足以影响电子自旋进动的磁场。这种感应场强烈地降低了电子的自旋极化。因此，开发一些方法来克服这个问题对于器件应用是重要的。