Selective Spin Injection Controlled by Electrical way in Ferromagnet/Quantum Dot/Semiconductor system

Selective and large polarization of current injected into semiconductor (SC) is predicted in Ferromagnet (FM)/Quantum Dot (QD)/SC system by varying the gate voltage above the Kondo temperature. In addition, spin-dependent Kondo effect is also revealed below Kondo temperature. It is found that Kondo resonances for up spin state is suppressed with increasing of the polarization P of the FM lead. While the down one is enhanced. The Kondo peak for up spin is disappear at P=1.