Properties of spin polarization and spin transport for zigzag antimonene nanoribbons with single vacancies

Defects are unavoidable in two-dimensional materials which may change their geometric structures and intrinsic physical properties. Based on the spin-polarized density functional theory and the non-equilibrium Green's function method, we have investigated the spin polarization and spin transport properties of zigzag antimonene nanoribbons (Z-SbNRs) with vacancy defect at different positions. It can be found that the ground state of the defective Z-SbNRs transforms from ferromagnetism (FM) to anti-ferromagnetism (AFM) when the position of the vacancy varies and spin polarization is induced by the vacancy defect. The calculated band structures show that all energy bands split and the defective Z-SbNRs exhibit semiconductor characteristics with smaller band gaps when comparing with the perfect Z-SbNRs. From the analysis of current-voltage characteristic, it can be observed that the threshold voltages of the defective Z-SbNRs are smaller and spin-resolved currents are larger than that of the perfect Z-SbNRs. Interestingly, the spin polarization and spin transport properties of defective Z-SbNRs are sensitive to the position of the single vacancy, which means the properties can be tuned by varying the position of the vacancy. The results indicate that the Z-SbNRs with the single vacancy is a promising candidate in spintronic devices.