Spin-resonant tunneling in ferromagnetic conductor/ semiconductor heterostructure for spin-filter application

Abstract

Spin-dependent tunneling in a ferromagnetic conductor/ semiconductor is analyzed with zero external fields. The barrier transparency, dwell time, tunneling time of electrons through heterostructure and the degree of polarization efficiency are calculated in Fe/GaAs double barrier heterostructure. The polarization efficiency of Fe/GaAs and Fe/InAs double-barrier heterostructures are compared. The Fe/GaAs has a high degree spin-polarization than Fe/InAs structure. The barrier transparency peak is sharper at the high width of the barrier. The results show that the polarization efficiency is maximum when the barrier width is maximum. The tunneling lifetime of electrons is evaluated using Heisenberg’s uncertainty principle. The spin components are completely separated at high barrier width and hence can be used effectively as a spin filter.