Spin-filter diode based on ZnSe/Zn1-xMnxSe/Zn1-yMnySe/ZnSe heterostructures

We propose and demonstrate a spin-filter diode based on semimagnetic semiconductor ZnSe/Zn1-xMnxSe/Zn1-yMnySe/ZnSe heterostructures. It is found that the degree of spin polarization greatly depends on the electric field direction and its magnitude. There is significant difference of the spin polarization between under forward bias and under reverse bias. It is also found that the spin polarization will reverse under relatively small magnetic field, which is originated from resonant enhancement effect for spin-up electrons tunneling through effective steplike potential of the corresponding structure. (C) 2002 American Institute of Physics.