Quantum Spin Hall Effect and Tunable Spin Transport in As-Graphane.

Tunable spin transport in nanodevices is highly desirable to spintronics. Here, we predict existence of quantum spin Hall effects and tunable spin transport in As-graphane, based on first-principle density functional theory and tight binding calculations. Monolayer As-graphane is constituted by using As adsorbing on graphane with honeycomb H vacancies. Owing to the surface strain, monolayer As-graphane nanoribbons will self-bend toward the graphane side. The naturally curved As-graphane nanoribbons then exhibit unique spin transport properties, distinctively different from the flat ones, which is a two-dimensional topological insulator. Under external stress, one can realize tunable spin transport in curved As-graphane nanoribon arrays. Such intriguing mechanical bending induced spin flips can offer promising applications in the future nanospintronics devices.