College of Physical Sciences, Graduate University of Chinese Academy of Sciences, PO Box 4588, Beijing 100049, People's Republic of China.
J Phys Condens Matter. 2010 May 12;22(18):186004. doi: 10.1088/0953-8984/22/18/186004. Epub 2010 Apr 20.
The spin transfer effect in a ferromagnet-quantum dot (insulator)-ferromagnet Aharonov-Bohm (AB) ring system with Rashba spin-orbit (SO) interactions is investigated by means of the Keldysh nonequilibrium Green function method. It is found that both the magnitude and direction of the spin transfer torque (STT) acting on the right ferromagnet electrode can be effectively controlled by changing the magnetic flux threading the AB ring or the gate voltage on the quantum dot. The STT can be greatly augmented by matching a proper magnetic flux and an SO interaction at a cost of low electrical current. The STT, electrical current and spin current are uncovered to oscillate with the magnetic flux. The present results are expected to be useful for information storage in nanospintronics.
在具有拉什巴自旋轨道（SO）相互作用的铁磁体-量子点（绝缘体）-铁磁体阿哈罗诺夫-玻姆（AB）环系统中，通过凯尔德什非平衡格林函数方法研究了自旋转移效应。研究发现，通过改变穿过 AB 环的磁通量或量子点上的栅极电压，作用在右铁磁电极上的自旋转移扭矩（STT）的大小和方向都可以得到有效控制。通过匹配适当的磁通量和 SO 相互作用，可以以较低的电流代价大大增加 STT。STT、电流和自旋电流都发现随着磁通量的变化而振荡。本研究结果有望在纳米自旋电子学中的信息存储方面得到应用。
