Rectifying and spin filtering behavior of aluminum doped silicon carbide nanoribbons: the first principles study

In this paper, spin transport properties of aluminum-doped zigzag silicon carbide nanoribbons (Al-ZSiC NRs) are investigated using the first-principle calculations and the nonequilibrium Green's function method. The results show an approximately perfect spin filtering (100%) for three considered models and undoped structure at ferromagnetic state in the presence of bias voltage. In particular, a weak negative differential resistance (NDR) phenomenon can be obtained in a certain system when replacing the edge Si atom with the Al-doping atom. Indeed, edge states play a crucial role in spin-dependent transport and magnetic properties of ZSiC NRs, such as the NDR effect. Furthermore, the significant rectifying ratio (RR) is obtained under bias voltage only for one given configuration. When the same spin states overlap in the bias window (BW), spin-dependent transmission and the spin current display a non-zero value; however, the mismatch of the same spin states within the BW region causes to vanish the transmission spectra. The controllable manipulation of threshold voltage, spin filtering efficiency, NDR behavior, and RR effect can be achieved by substituting of silicon with Al atom in ZSiC NRs. These results shed new light on our understanding of silicon carbide-based nanodevices with appealing spintronic applications.