论文部分内容阅读
利用演化算符的方法,研究了量子点体系中的电流以及自旋流,该体系中量子点和左右磁性电极耦合并且受到微波作用,且两电极之间有直接隧穿,得到了体系电流的解析表达式.发现对于无直接隧穿和零偏压情况,无论对称结构还是非对称结构,电流和自旋流总为零.对于直接隧穿和零偏压情况,对于两边为非对称结构,微波场辐射在量子点上可以导致自旋流而非零的总电流,给出了平行和反平行磁构型下的结果并进行了讨论;对于两边为对称结构结构,平行磁构型下,量子点上加微波场时自旋流和总电流均为零;在反平行磁构型下,量子点上加微波场可以导致自旋流而总电流为零,这可以作为设计自旋电池的一个方案,并且在目前技术条件下实验上也是可行的.
Using evolutionary operator, the current and the spin current in the quantum dot system are studied. In this system, the quantum dots are coupled with the left and right magnetic electrodes and are subjected to microwaves. The direct current tunneling between the two electrodes gives the current It is found that the current and the spin flow are always zero for both direct tunneling and zero-bias case, and asymmetric structure for both sides, The microwave field radiation can lead to spin current instead of zero total current at quantum dot. The results under parallel and antiparallel magnetic configurations are given and discussed. For both sides of symmetrical structure, under parallel magnetic configuration, In the anti-parallel magnetic configuration, adding a microwave field to a quantum dot can result in a spin-current and a total current of zero, which can be used as a design spin cell A program, and experimentally feasible under the current technical conditions.