稀磁半导体异质结构的自旋极化输运性质

Spin-polarized Transport Properties in Diluted Magnetic Semiconductor Heterostructures

采用格林函数方法和群速近似研究在电场、磁场作用下电子渡越稀磁半导体异质结构的自旋过滤及自旋分离的特征。研究表明具有不同自旋指向的极化电子渡越同一稀磁半导体异质结构 ,不仅隧穿几率存在着显著的差异 ,而且渡越时间的差异可达几个数量级。这种差异随着外磁场的增强而加大 ,而随外电场的增强而减小。结果意味着稀磁半导体异质结构具有很好的自旋过滤效果 。

Spin filtering and spin separation characteristics in diluted magnetic semiconductor heterostructures in the presence of both external electric field and magnetic field have been investigated by using of the Green′s function method and group velocity approximations. The results indicate that there exist great discrepancies in the transmission coefficient for electrons with different spin orientations through the same diluted magnetic semiconductor heterostructure, and the difference of the tunneling times can reach by up to several orders of magnitude. The difference can be enhanced by the external magnetic field while it is reduced by the external electric field. The results imply that not only the diluted magnetic semiconductor heterostructure possess good spin filtering but also polarized electrons can be separated in time during tunneling through such a kind of structure.