چكيده به لاتين
The spin-dependent transport properties of zigzag silicon carbide naonoribons (ZSiCNRs) in the presence of edge hydrogenation are investigated by using non-equilibrium Green’s functions (NEGF) in the framework of density functional theory (DFT). Four possible H-passivated edge configurations are considered. The obtained formation energy shows that, under standard conditions, the most stable edge hydrogenated configuration is 2H-2H structure instead of the 1H-1H. In addition, the silicon atoms choose the sp3 hybridization, unlike carbon atoms that prefer the sp2 hybridization. The results of I-V characteristics show that perfect spin filtering effect (100%) in 1H-1H, 1H-2H, 2H-1H cases can be observed that have the potential applications in spintronic devices. Moreover, the current-limited effect and negative differential resistance (NDR) phenomenon are observed in the 1H-1H and 2H-2H cases, respectively. Moreover, the spin transport properties of the N/B-doping zigzag-edged silicon carbide nanoribbons (ZSiCNRs) with the asymmetric edge hydrogenation are studied. Our findings show, the N atom substitutes with C site while the B atom prefers to be localized at the Si site. Also, the B and N doped ZSiCNRs exhibit half-metallic, metallic, and bipolar semiconductor behavior at ferromagnetic or antiferromagnetic states, which the possibility of designing of spin nanodevices would be provided. The obtained I-V characteristic shows a perfect spin filtering effect (100%) in such N/B doping ZSiCNRs with an asymmetric edge. In addition, Based on asymmetric edge hydrogenation of zigzag silicon carbide nanoribbons (ZSiCNRs), the nanojunction with the boron and nitrogen impurity are constructed. The spin transport properties of nanojunction are calculated in different magnetic configurations as parallel and antiparallel configurations, respectively. In P configuration, the I-V curves display spin-down filtered in the bias range of -0.5 V to 0.2 V. Also, it shows NDR phenomenon in positive and negative bias. The I-V characteristic of AP configuration indicates that the spin-up currents cannot flow through the nanojunction, and spin filtering effect occur in the bias range of -0.5 V to 0.2 V. Moreover, in the AP configuration, the NDR phenomenon is specified in positive bias voltage. These findings indicate that B/N-doped 2H-1H nanojunctions can integrate several useful functions in controlling spin current.
