Structural and electronic study of nanoscrolls rolled up by a single graphene sheet

With special topology differing from nanotubes, carbon nanoscrolls (CNSs) rolled up by a single graphene sheet show unique properties and have potential applications in hydrogen storage and energy storage. We studied various types of nanoscrolls by using first principle calculation. The minimum innermost radius of armchair-type nanoscrolls is achieved. The electronic structures of nanoscrolls are greatly related to chirality (n,m). Armchair nanoscrolls are metallic or semimeatllic depending on their sizes and those metallic ones have larger density of states at the Fermi level than metallic single-walled nanotubes (SWNTs). Zigzag nanoscrolls are semiconductors with energy gaps much smaller than corresponding zigzag SWNTs; moreover, they get small gaps at (16,0) and (19,0), while zigzag SWNTs have small gaps at (3n,O).