Studies On Spin-polarized Transport Properties In Aperiodic Semiconductor Multilayers Heterostructures

In recent years, spintronics has become a rapidly growing area. It is a new cross-field based on the study of mesoscopic and micro-scale range of spin-polarized electron transport properties (including spin polarization, spin scattering and spin relaxation, etc), and the spin-polarized electronic transport has become one of the majors of the rapidly developed spintronics. In this paper, we study the spin-dependent transport and the spin-dependent shot noise properties of electron in aperiodic cascade junctions of semiconductors. The main results obtained in this paper are listed below:(1) Based on the transfer matrix method, we have investigated the spin-dependent transport in aperiodic semiconductor multilayers heterostructures. We have calculated the spin-dependent transmission coefficients, the spin polarization, and the spin conductance by changing the percentage of the thicknesses of block A and B, the Rashba spin-orbit coupling, and the generation of the T-M sequence. The results indicate that there is an evident quantum size effect. With increasing the thicknesses of block A and B and the generation of the T-M sequence, the spin-dependent transmission coefficients and the spin polarization show an evident aperiodic oscillation. A spin-dependent bandgap structure is realized, high spin-polarization has been observed and the spin conductance exist the value of zero by tuning the Rashba spin-orbit coupling.(2)On the basis of the Landauer-Büttiker scattering formalism and considering the presence of the Rashba spin-orbit interaction and an electric field, we have investigated the spin-dependent short noise properties of electron tunneling through the sixth generation of semiconductor heterostructures . The spin-dependent short noise and Fano factor with the thicknesses of block A and B, the Rashba spin-obit interaction and the external bias voltage in the two ferromagnetic contacts have been numerically calculated and discussed. The results indicate that there is an evident quantum size effect and the shot noise becomes strongly spin-dependent; short noise and Fano factor have an aperiodic oscillation.