Transmissividade de Spins Polarizados em dupla barreira simétrica

Abstract

In this dissertation, the scattering matrix technique is used to calculate the transmissivity of polarized spins through semiconductors heterostructures of symmetrical double barrier. The movement of electrons is described in the effective mass approach of the complete Dresselhaus models. The transmissivity and polarization are calculated as a function of electron energy with kjj = 0; 5x106cm􀀀1, kjj = 1x106cm􀀀1 and kjj = 2x106cm􀀀1 varying the angle GaSb=GaxAl1􀀀xSb=GaSb=GaxAl1􀀀xSb=GaSb system. Fixing the parallel moment kjj and varying = 30o, 45o, 60o and 90o, we observed that the positions of the resonant picks vary faintly with the energy and the transmission curves change more strongly in the areas out of the resonance, with the polarization reaching values among 54%􀀀!82% in the resonant levels. For the direction = 45o, the spin mixing produces a spin polarization efficiency of nearly 100 %. Applying an external voltage, the peak transmissivity and spin polarization undergo a shift towards regions to lower energies.