▎ 摘　　要

We present a first-principles study of electronic and transport properties of a novel W-shaped graphene nanoribbon (W-GNR) structure that comprises hybrid GNR segments with alternating armchair and zigzag edges. Such hybrid W-GNRs exhibit semiconducting characteristics with distinct properties that stem from a unique combination of the features of the armchair and zigzag constituents. When the ribbon is narrow, the interplay of the two GNR components leads to much reduced variation in band gap. The spin-polarized edge states of the zigzag GNR engender an electric-field-driven half-metallicity. Moreover, spin-dependent density of states at the band edge produces asymmetric spin transmission coefficients, yielding unequal spin currents under a large bias voltage. These findings suggest that these new W-GNRs hold great promise for applications in nanoscale spintronic devices. (C) 2011 American Institute of Physics. [doi:10.1063/1.3669496]