THEORY OF SPIN-DEPENDENT TRANSPORT IN HYBRID NANOSTRUCTURES

混合纳米结构中自旋相关输运理论

基本信息

批准号：
15540328
负责人：
TAKAHASHI Saburo
金额：
$ 0.96万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

1.We studied the nonlocal spin transport in a device consisting of a nonmagnetic metal (N) and ferromagnetic injector and detector electrodes connected to N. We solve the spin-dependent transport equations in a device with arbitrary interface resistance, and obtain the optimal conditions for efficient spin injection, accumulation, and spin transport in the device. We proposed a nonlocal spin manipulation by using the nonlocal spin-current injection technique.2.We studied the nonlocal Andreev reflection in a device consisting of two ferromagnetic wires attached to a superconductor, and clarified the range over which the crossed Andreev reflection takes place.3.We proposed a new superconducting qubit which consists of a superconducting ring with ferromagnetic junctions and an ordinary Josephson junction. A quantum coherent two-level state is formed without an external magnetic field. This feature makes it possible to reduce the size leading to a long decoherence time.4.We studied the electronic structure of a magnetic impurity and the ferromagnetic interaction between magnetic impurities in a semiconductor using the Haldane-Anderson model, and obtain a long-range ferromagnetic exchange interaction between the localized moments due to the overlapping of the extended spin densities around the impurities.5.We proposed a method for estimating the strength of spin-orbit scattering by impurities in non-magnetic metals. We show that the pure spin current created by the nonlocal spin-injection technique produces a nonlocal Hall voltage, which is measurable by experiments.6.We constructed a microscopic theory describing the interaction between spin current and a domain wall, and presented new equations of motion for domain walls. We proposed nano-structured magnetic memories utilizing the current-driven domain wall motion.

1.我们研究了由非磁性金属（N）和连接到N的铁磁注入器和探测器电极组成的器件中的非局域自旋输运。我们求解了具有任意界面电阻的器件中的自旋相关输运方程，并获得了最佳条件用于器件中高效的自旋注入、积累和自旋传输。我们提出了利用非局域自旋电流注入技术进行非局域自旋操纵。2.研究了由两根铁磁线连接到超导体的装置中的非局域安德烈夫反射，并阐明了交叉安德烈夫反射发生的范围。 3.我们提出了一种新型超导量子位，它由具有铁磁结的超导环和普通约瑟夫森结组成。无需外部磁场即可形成量子相干二能级态。这一特性使得减小尺寸成为可能，从而导致较长的退相干时间。4.我们利用Haldane-Anderson模型研究了磁性杂质的电子结构以及半导体中磁性杂质之间的铁磁相互作用，并获得了长程由于杂质周围的扩展自旋密度重叠而导致局域矩之间的铁磁交换相互作用。5.我们提出了一种估计非磁性金属中杂质引起的自旋轨道散射强度的方法。我们证明，非局域自旋注入技术产生的纯自旋电流会产生非局域霍尔电压，该电压可以通过实验测量。6.我们构建了描述自旋电流与畴壁之间相互作用的微观理论，并提出了新的方程：畴壁的运动。我们提出了利用电流驱动磁畴壁运动的纳米结构磁存储器。

项目成果

期刊论文数量（84）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Andreev reflection in ferromagnet/superconductor/ferromagnet structures

铁磁体/超导体/铁磁体结构中的安德烈夫反射

DOI：
发表时间：
2003
期刊：
Physica E 18
影响因子：
0
作者：
T.Watanabe;H.Yokoyama;Y.Tanaka;J.Inoue;M.Ogata;S.Takahashi;T.Yamashita;S.Takahashi;T.Yamashita;H.Imamura;T.Yamashita;S.E.Barnes;S.Kaji;T.Yamashita;T.Yamashita;S.Kaji;T.Yamashita;T.Yamashita;S.Maekawa;S.Kaji;J.Martinek;前川禎通;T.Yamashita
通讯作者：
T.Yamashita

T.Yamashita, S.Takahashi, S.Maekawa: "Crossed Andreev reflection in structures consisting of a superconductor with ferromagnetic leads"Phys.Rev.B. 68. 174504(1)-174504(8) (2003)

T.Yamashita、S.Takahashi、S.Maekawa：“由具有铁磁引线的超导体组成的结构中的交叉安德烈夫反射”Phys.Rev.B。