四端双量子点系统中的自旋和电荷能斯特效应

发布时间：2018-06-02 16:21

  本文选题：量子点 + 能斯特效应　； 参考：《物理学报》2017年09期

【摘要】：基于非平衡态格林函数方法,理论研究了与四个电极耦合的双量子点系统中的自旋和电荷能斯特效应,考虑了不同电极的磁动量结构和量子点内以及量子点间电子的库仑相互作用对热电效应的影响.结果表明铁磁端口中的磁化方向能够有效地调节能斯特效应:当电极1和电极3中的磁化方向反平行排列时,通过施加横向的温度梯度,系统中将会出现纯的自旋能斯特效应;当电极4从普通金属端口转变为铁磁金属端口时,将同时观测到电荷和自旋能斯特效应.研究发现,能斯特效应对于铁磁电极极化强度的依赖程度较弱,但对库仑排斥作用十分敏感.在量子点内和点间库仑排斥作用的影响下,自旋及电荷能斯特系数有望提高两个数量级.
[Abstract]:Based on the Green's function method of nonequilibrium states, the spin and charge Nernst effects in a two-quantum dot system coupled with four electrodes are studied theoretically. The influence of the magnetic momentum structure of different electrodes and the Coulomb interaction of electrons in quantum dots and quantum dots on the thermoelectric effect is considered. The results show that the magnetization direction in the ferromagnetic port can effectively adjust the Nernst effect: when the magnetization direction in electrode 1 and electrode 3 is antiparallel, the pure spin Nernst effect will appear in the system by applying the transverse temperature gradient. When the electrode 4 changes from the ordinary metal port to the ferromagnetic metal port, both the charge and the spin Nernst effect will be observed at the same time. It is found that the Nernst effect is less dependent on the polarization intensity of ferromagnetic electrodes but sensitive to Coulomb repulsion. The spin and charge Nernst coefficients are expected to increase by two orders of magnitude under the influence of Coulomb repulsion in and between quantum dots.
【作者单位】： 渤海大学新能源学院;首都师范大学初等教育学院;清华大学物理系;量子物质科学协同创新中心;
【基金】：国家自然科学基金(批准号:11547209,11604021,11574173) 辽宁省博士科研启动基金指导计划(批准号:201601352) 低维量子物理国家重点实验室开放课题(批准号:KF201613) 北京市教育委员会科技计划一般项目(批准号:KM201410028021)资助的课题~~
【分类号】：O471.1
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本文编号：1969409