Spin-dependent Shot Noise In Fractal Semiconductor Multilayers With Two Ferromagnetic Contacts

摘要

We investigate the spin-dependent shot noise properties of electrons tunneling through fractal semiconductor multilayers (FSMs) sandwiched between two ferromagnets (Fs) with arbitrary relative magnetization direction in the presence of the Rashba spin-orbit interaction and an electric field. Within the framework of the Landauer-Buettiker scattering formalism, the current, shot noise, and Fano factor of the F/FSM/F heterostructures are numerically calculated and compared with those of periodic semiconductor multilayers (PSMs) again with ferromagnetic contacts. The results indicate that the shot noise becomes strongly spin dependent and can be greatly modulated not only by the external electric field and Rashba spin-orbit interaction but also by the structural configuration and length of the semiconductor multilayers. Interestingly, compared to the F/PSM/F heterostructures, the current, shot noise, and Fano factor of the F/FSM/F heterostructures can exhibit a more marked quantum size effect, along with typical low-frequency aperiodic oscillations as the bias voltage or the Rashba spin-orbit coupling strength increases. There is little Rashba spin-orbit coupling strength dependence with increasing angle between the two magnetic moments of the left and right ferromagnets.