Abstract: Based on the infinite-U Anderson model, Keldysh Green Function was used to calculate the Kondo splitting of DOS (Density of State) in quantum dot induced by a side?coupled magnetic impurity. Because of the normalization for quantum dot energy caused by the ferromagnetic lead, the Kondo peak in DOS splits. It?s shown that the polarization of the magnetic leads and the azimuth of the impurity spin set off the Kondo resonant splitting in the DOS. For the antiparallel configuration of lead magnetization, the localization of the peaks is hardly influenced by the magnetic impurity. For the parallel configuration, three Kondo peaks appear in the DOS and the interval of the peaks depends on the impurity spin azimuth. The splitting in the DOS induced by the magnetic leads can be compensated by the side?coupled impurity, if the polarizations of the magnetic leads are choosed rightly.

Key words: quantum dot system, Keldysh green function, Kondo effect

摘要： 讨论了一个耦合于量子点的磁性杂质，当两边是铁磁性导线时量子点上电子的态密度Kondo峰的变化情况。用格林函数运动方程的方法和特定的自洽方法得到了态密度的解析表达式。杂质与量子点上电子的耦合使得原本简并的电子能级分裂。数值计算结果表明当两边的铁磁导线极化反平行时，态密度的Kondo峰几乎不随着磁性杂质方位角的变化而变化。当极化平行时，会出现3个Kondo峰，并且峰之间的间隔随着杂质的方位角的增大而增大。如果选取适当极化率的铁磁导线，由导线的铁磁性引起的Kondo峰的分裂可以被杂质的耦合作用抵?消掉。?

关键词: 量子点系统, Keldysh格林函数, Kondo效应