Inducing metallicity in graphene nanoribbons via zero-mode superlattices

The design and fabrication of robust metallic states in graphene nanoribbons (GNRs) are challenging because lateral quantum confinement and many-electron interactions induce electronic band gaps when graphene is patterned at nanometer length scales. Recent developments in bottom-up synthesis have enabled the design and characterization of atomically precise GNRs, but strategies for realizing GNR metallicity have been elusive. Here we demonstrate a general technique for inducing metallicity in GNRs by inserting a symmetric superlattice of zero-energy modes into otherwise semiconducting GNRs. We verify the resulting metallicity using scanning tunneling spectroscopy as well as first-principles density-functional theory and tight-binding calculations. Our results reveal that the metallic bandwidth in GNRs can be tuned over a wide range by controlling the overlap of zero-mode wave functions through intentional sublattice symmetry breaking.

Source: ScienceNOW - September 23, 2020 Category: Science Authors: Rizzo, D. J., Veber, G., Jiang, J., McCurdy, R., Cao, T., Bronner, C., Chen, T., Louie, S. G., Fischer, F. R., Crommie, M. F. Tags: Chemistry, Physics r-articles Source Type: news