Perfect spin filtering of T-shaped device based on the zigzag silicon carbide nanoribbons

Abstract

How to generate stable and pure spin-polarized current in nanodevice based on low-dimensional magnetic materials and systems has attracted extensive attention. In this work, using the non-equilibrium Green’s function (NEGF) combined with density-functional theory (DFT), we predict highly conductive transport and perfect spin filtering of the novel T-shaped device, which is constructed by a finite armchair silicon carbide nanoribbon (ASiCNR) connected to one edge of an infinite zigzag silicon carbide nanoribbon (ZSiCNR). This particular performance is due to the fact that there are always two edge states contributing to electron transport around the Fermi level, no matter whether the ZSiCNR is in the ferromagnetic or anti-ferromagnetic state. As a consequence, the T-shaped device would ideally yield 100% spin-polarized current with one spin channel blocked by the ASiCNR part. Moreover, it is found that such blocking effect is independent of the shape of the ASiCNR part. Based on the above analysis, it is easily predicted that such pure spin-polarized current could also be obtained in the device constructed by ZSiCNRs, as long as one pristine edge of ZSiCNRs is defected by doping, absorbing, vacancies and so on, which opens new possibility of two dimensional silicon carbide in spintronic device applications.