arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2103.16059cond-mat.mes-hall
收藏

基于双量子点的大电压可调自旋阀

Large voltage-tunable spin valve based on a double quantum dot

Patrycja Tulewicz, Kacper Wrzesniewski, Szabolcs Csonka, Ireneusz Weymann

摘要:

研究了基于双量子点的自旋阀的自旋相关输运性质。假设每个量子点与其自身的铁磁铅强耦合,而量子点之间的耦合相对较弱。通过系统的电流是在点之间的跳跃微扰理论内确定的,而量子点-铁磁铅子系统的光谱是通过数值重整化群方法确定的。铁磁体和量子点之间自旋相关的电荷涨落产生了一个有效的交换场,使双量子点能级分裂。对于每个量子点,可以通过栅极电压或通过改变外部引线的磁配置来单独地控制这样的场。我们证明,所考虑的双量子点自旋阀设置具有增强的磁阻特性,包括正常和反向隧道磁阻。我们还表明,该系统允许产生高自旋极化电流,这可以通过纯电气手段控制。所考虑的双量子点与铁磁接触,因此可以作为一个有效的电压可调的自旋阀,其特征在于高输出参数。

英文摘要:

We study the spin-dependent transport properties of a spin valve based on a double quantum dot. Each quantum dot is assumed to be strongly coupled to its own ferromagnetic lead, while the coupling between the dots is relatively weak. The current flowing through the system is determined within the perturbation theory in the hopping between the dots, whereas the spectrum of a quantum dot-ferromagnetic lead subsystem is determined by means of the numerical renormalization group method. The spin-dependent charge fluctuations between ferromagnets and quantum dots generate an effective exchange field, which splits the double dot levels. Such field can be controlled, separately for each quantum dot, by the gate voltages or by changing the magnetic configuration of external leads. We demonstrate that the considered double quantum dot spin valve setup exhibits enhanced magnetoresistive properties, including both normal and inverse tunnel magnetoresistance. We also show that this system allows for the generation of highly spin-polarized currents, which can be controlled by purely electrical means. The considered double quantum dot with ferromagnetic contacts can thus serve as an efficient voltage-tunable spin valve characterized by high output parameters.

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。

↑