Asymmetry and separation of spin tunneling time in ZnSe/Zn_1-xMn_xSe multilayers

We investigate characteristics of spin tunneling time in ZnSe/Ze_1-xMn_xSe multilayers under the influence of both an electric field and a magnetic field. The results indicate that the tunneling time shows complicated oscillations and significant spin separation for electrons with different spin orientations traversing semimagnetic semiconductor heterostructures. It is also shown that the tunneling time exhibits obvious asymmetry in opposite tunneling directions for electrons tunneling through asymmetric heterostructures, which mainly occurs in resonant regions. The degree of the asymmetry of the tunneling time is not only spin-polarization dependent but also external-field induced.