The design of bipolar spin filtering junction in zigzag silicene nanoribbons

We performed first-principles simulation on the electronic structure of zigzag silicene nanoribbons (ZSiNRs), and found that semi-hydrogenation can break the extended p-bonding network of silicene, leaving the electrons in the unsaturated Si atoms localized and unpaired, and ferromagnetic semi-conducting behavior can be obtained. While the fully hydrogenated ZSiNRs are found to be energetically degenerate and show wide band-gap semiconductor feature. Then, we designed and investigated the spin-dependent electron transport of a heterostructure, consisting of semi-hydrogenation ZSiNRs and ZSiNRs. The results show a perfect dual spin filtering effect at the parallel and antiparallel spin configuration with large bias range. The spin dependent electron transmission spectrum, band structure, transmission pathway, and the molecularly projected self-consistent Hamiltonian state are employed to investigate the physical origin of the spin-polarized effect. (C) 2016 Elsevier B.V. All rights reserved.