Spin multiple functional devices in zigzag-edged graphyne nanoribbons based molecular nanojunctions

Graphyne, a two-dimensional carbon allotrope being proven to possess amazing electronic properties as graphene, have been successively proposed in theory and experiment. Here, the electronic band structures of zigzag-edged graphyne nanoribbons (Z GYNR) and zigzag-edged graphyne nanoribbons (Z GYNR) have been revealed with a metallic behavior in non-magnetic state, a metallic spin splitting in ferromagnetic state and a spin degeneracy with a direct band gap in antiferromagnetic state, which is much similar to zigzag-edged graphene case. We also report a comprehensive study of the intrinsic spin-resolved transport properties for the three junctions with a carbon chain sandwiching between Z GYNR/Z GYNR leads by using density functional theory coupled with the non-equilibrium Green's function method. The results reveal that the designed junctions perform multiple functions with wonderful spin filtering, rectification, and a spin negative differential resistance(SNDR) effect, and so on. Specifically, the spin filtering efficiency approximate 100% within a large bias range, the maximum rectification ratio can be up to 1.5 x 10(4) and an obvious SNDR with the maximum peak to valley ratio up to 9.10 x 10(3) can also be found. The GYNR-based multiple functional device is demonstrated, and mechanisms are proposed for the above phenomena.