Study Of Spin-polarized Transport Through Quantum Dots

The spin-polarized dependent electronic transport through mesoscopic structure has become one of the majors of the rapidly developed spintronics. This paper is firstly to be introduced some typical effects in mesoscopic transport including weak localization effect, Ahoronov-Bohm oscillation, universal conductance fluctuations, and some fundamental concepts in spintronics, such as Giant magnetoresistance effect, spin injection, spin transistors and so on;Then the nonequilibrium Green Function technique, which is a normal method to deal with the mesoscopic transport, is described. Finally we use this method to investigate theoretically the electron transport through two lateral quantum dots between which the spin-polarization dependent tunneling occurs. Considering the intradot electron-electron Coulomb interaction, the Green Function is solved with the help of equation of motion and under the Hartree-Fock approximation. The numerical results indicate the oscillations of the spin current and the increase of the charge current with bias voltage, which can be explained qualitatively by the picture of spin-dependent resonant tunneling. This double-quantum-dot model can be used to yield spin-polarized current or act as a spin device.