LAUSR

Abstract Among the planar nanostructures, the Z-shaped nanoribbon junction which can be etched from a two-dimensional material sheet, is the one of the most promising device model for integration in multifunctional nanodevices. Here we propose a Z-shaped junction comprising a few-nanometer-long armchair-edged α-graphyne nanoribbon (αGYNR) embedded between two semi-infinite zigzag-edged αGYNR leads with parallel or antiparallel magnetic configuration. By ab initio calculations based on the non-equilibrium Green's function formalism combined with density functional theory, we study the electron spin-dependent transport properties for the junction under the influence of symmetric and asymmetric hydrogenation or fluorination edge treatments acted on αGYNRs, respectively. It is found that the edge passivation plays a pivotal role on the spin-charge transport of a Z-shaped αGYNR junction since the electron transport is mainly driven by the edge states of the system. Interestingly, the edge fluorination enhances charge transport but the double fluorinations treatment can suppress the edge transporting channels. Moreover, there exists an obvious effect of negative differential resistance in the designed junctions with peak to valley ratio reaching up to 4696. The possible physical/chemical mechanisms are revealed and discussed by studying the match degree of the band structure of the electrodes with the spin-resolved transmission spectrum around the Fermi level, as well as the evolution of the frontier molecular orbitals under certain bias. Our results imply that this Z-shaped αGYNR junction is a promising candidate in the future all-carbon device designing.