Photon-Assisted Spin-Dependent Tunneling in a Magnetic-Field Tunable Diluted Magnetic Semiconductor Structure with a Nonmagnetic Barrier

Using the Floquet theory and effective-mass approximation theory, we have investigated the terahertz (THz) photon-assisted transport through a magnetic-field tunable diluted magnetic semiconductor (DMS) structure with a nonmagnetic barrier under multi-physical fields, including an external magnetic field, an electric field and a THz field. It is found that a THz field and an electric field can greatly affect the transmission coefficient and current density as well as the corresponding polarizations. As a result, some asymmetric Fano type transmission resonance appear at some specific energy. With the applied bias increasing, some quasi platforms of the polarization began to take shape. Furthermore, the transmission coefficient suppression or augmentation can be clearly seen from the variation tendency of current density. It is noteworthy that the amplitude of current density polarization becomes larger under a THz field and a small magnetic field. These remarkable properties of spin polarization might be beneficial to the design of spin filtering devices.