Electromechanical switch in metallic graphene nanoribbons via twisting

We imposed screwing operation to a metallic ferromagnetic zigzag-edged graphene nanoribbon (ZGNR) with a narrow width and a finite length, and the polarized charge transport is investigated by using Nonequilibrium Green's function in combination with density functional theory. The current are nearly completely suppressed when the ZGNRs are overturned. Inspiringly, this metal-to-semiconductor transition tuned by screwing operation is reversible. Hence our investigation brings forward a novel electromechanical switch, and such a switch is equivalent to a spin valve without resort to an external magnetic field.

We propose a novel electromechanical switch via twisting a metallic ferromagnetic symmetric zigzag-edged graphene nanoribbon. The switch realizes a spin valve function in a flexible nanoribbon by twisting in addition to change in the magnetic field direction.Figure optionsDownload as PowerPoint slideHighlights
► Twisting a metallic ferromagnetic ZGNR is a possible way to make an electromechanical switch.
► Twisting would cause orbital symmetry mismatch of the two leads in a symmetric ferromagnetic ZGNR.
► Zero transmission gap is thus generated, and hence the current is suppressed.
► The switch series can be obtained via multiply overturning the nanoribbon.