▎ 摘　　要

We present first principles study based on spin polarized density functional theory for electronic properties of armchair graphene nanoribbons (AGNRs) and Bloch state study in zigzag graphene nanoribbons (ZGNRs) passivated with hydrogen atoms. We have investigated the spin-dependent band structure of zigzag graphene nanoribbons. It is observed that these zigzag ribbons are metallic without spin consideration while band gap opens up when spin included. We have also plotted conduction and valence band Bloch states for various k-points and observed that the two spin-components are localized on opposite sides of the ribbon.