Spin injection and spin control in magnetic/non-magnetic semiconductor quantum structures

磁性/非磁性半导体量子结构中的自旋注入和自旋控制

基本信息

批准号：
14205002
负责人：
OHNO Yuzo
金额：
$ 27.12万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

The purpose of the research is to establish fundamental technology for spintronics devices in which information is born and processed by spins. Here, we designed and fabricated ferromagnetic/non-magnetic semiconductor quantum structures and investigated the unique optical, electrical, and magnetic properties in those structures by controlling the spin states of carriers, nuclei, excitons, and magnetic ions with electrical and optical means. The achievements of the research are summarized as :1.We manifested that the efficiency of electrical electron spin injection in p-ferromagnetic/n^+-non-magnetic semiconductor tunnel junction sensitively depends on the thickness and doping concentration of n^+-GaAs interface layer by performing a systematic experiments, and showed the optimized condition.2.We studied the effect of anisotropic g-factor and hyperfine interaction in n-GaAs/AlGaAs (110) quantum wells by time-resolved Faraday rotation technique. We observed bistability and hysteresis of dynamic nuclear polarization, which were well reproduced by self-consistent calculation. We also evaluated the degree of dynamic nuclear polarization to be 30%.3.We demonstrated that the hyperfine interaction and dynamic nuclear polarization can be controlled by changing the background electron density with gate electric field in a gated n-GaAs/AlGaAs (110) quantum well. We showed that the experimental observation can be explained by metal-insulator transition, on which the hyperfine interaction depends sensitively.

该研究的目的是为Spintronics设备建立基本技术，其中信息是由旋转出生和处理的。在这里，我们设计和制造的铁磁/非磁性半导体量子结构，并通过控制电气和光学手段的载体，核，激子和磁离子的旋转状态来研究这些结构中独特的光学，电气和磁性。研究的成就总结为：1。我们表明，电气电子自旋注射在p-有效性/n^+ - 非磁性半导体隧道连接处的效率敏感的厚度和掺杂浓度取决于N^+-GAAS界面层的厚度，并通过进行系统的效果。 N-GAAS/ALGAAS（110）量子孔中的超细相互作用通过时间分辨的法拉第旋转技术。我们观察到动态核极化的双重性和滞后性，这些核极化是通过自洽的计算很好地重现的。我们还评估了动态核极化的程度为30％。3。我们证明，可以通过在封闭式的N-GAAS/ALGAAS（110）量子井中使用栅极电场改变背景电子密度来控制超精细相互作用和动态核极化。我们表明，可以通过金属 - 绝缘体过渡来解释实验观察，而超精细的相互作用敏感。