Magnetic Field On The Electronic Spin In The Polarized Transport In Ferromagnet / Semiconductor / Ferromagnetic Heterojunction

In this work we have made a investigation on electronic phenomena in both quasi one-dimensional FM/S/FM (Fe/InAs/Fe) system with an applied magnetic field and T-structure which is fabricate by ferromagnetic and semiconductor with an applied magnetic field. Based on the heterostructures with an applied magnetic field We reveal some new effects.(l)We have studied the effects of the applied magnetic field on spin-polarized transport through a quasi one-dimensional Fe/InAs/Fe heterostructure with a tunnel barrier. In the calculation through changing the length of the semiconductor;increasing the intensity of the Rashba spin-orbit coupling and the height of the tunnel barrier;changing the strength of the applied magnetic field we get the results .The results indicate that the applied magnetic field has an important effect on spin-polarized transport with the same length of the semiconductor and the transmission coefficients as the function of the Rashba spin-orbit coupling . When the magnetic filed becomes large, the resonant peaks shift to left, at the same time the transmission coefficients oscillate more rapidly, when the transmission coefficients as the function of length of the semiconductor the magnetic field has also an large effect on spin-polarized transport with the same intensity of the Rashba spin-orbit coupling. All this have indicate that applied magnetic field made important effect on spin-polarized transport through aFe/InAs/Fe heterostructure.(2) We have studied the effects of the applied magnetic field on spin-polarized transport through a Fe/InAs/Fe heterostructure which is T-structure. The results indicate that at the same length of semiconductor with the transmission coefficients as the function of the Rashba spin-orbit coupling , the applied magnetic field has important effects on the properties of spin-polarized transport, with the changing of applied magnetic field not only the location of the transmission coefficient has changed but also the peak of transmission coefficient changes .More important is that with the changing of applied magnetic filed , the transmission coefficient of spin-up electrons and spin-down electrons have different peak,: the peak of spin-up electrons is low than the spin-down electrons. When the magnetic becomes large, the transmission coefficients oscillate more rapidly. The results also indicate that at the same intensity of the Rashba spin-orbit coupling with the transmission coefficients as the function of the length of the semiconductor , with the changing of applied magnetic field not only the location of the transmission coefficient has changed but also the peak of the transmission coefficient changes. With the resuKs we calculate the spin polarization and get that the spin polarization changes widely when there is an applied magnetic flied .