arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0706.0152cond-mat.mes-hallcond-mat.supr-con
收藏

介观超导体-正常金属隧道结构中的非平衡自旋相关现象

Nonequilibrium spin-dependent phenomena in mesoscopic superconductor-normal metal tunnel structures

F. Giazotto, F. Taddei, P. D'Amico, Rosario Fazio, F. Beltram

摘要:

我们分析了广泛的自旋相关的非平衡输运性质的混合系统组成的正常区域隧道耦合到两个超导体与交换场引起的接近薄铁磁层,并突出其功能。通过计算正常区的准粒子分布函数,我们发现它们与自旋有关,并且对两个超导体中交换场之间的相对角度很敏感。讨论了非弹性碰撞对其性质的影响。结果发现,流经系统的电流强烈地依赖于交换场之间的相对角度,从而产生巨大的磁阻值。此外,电流呈现一个完整的自旋极化在一个广泛的偏置电压,即使在准平衡的情况下。在非平衡极限,我们参数化的分布与"有效"的温度,这原来是强烈的自旋依赖,虽然相当敏感的非弹性碰撞。通过隧道耦合的正常区域到一个额外的超导电极,我们表明,它是可能的,以实现两个自旋物种的自旋极化电流源,这取决于所施加的偏置电压。

英文摘要:

We analyze the broad range of spin-dependent nonequilibrium transport properties of hybrid systems composed of a normal region tunnel coupled to two superconductors with exchange fields induced by the proximity to thin ferromagnetic layers and highlight its functionalities. By calculating the quasiparticle distribution functions in the normal region we find that they are spin-dependent and strongly sensitive to the relative angle between exchange fields in the two superconductors. The impact of inelastic collisions on their properties is addressed. As a result, the electric current flowing through the system is found to be strongly dependent on the relative angle between exchange fields, giving rise to a huge value of magnetoresistance. Moreover, the current presents a complete spin-polarization in a wide range of bias voltages, even in the quasiequilibrium case. In the nonequilibrium limit we parametrize the distributions with an ``effective`` temperature, which turns out to be strongly spin-dependent, though quite sensitive to inelastic collisions. By tunnel coupling the normal region to an additional superconducting electrode we show that it is possible to implement a spin-polarized current source of both spin species, depending on the bias voltages applied.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑