ACS Nano. 2014 Jun 24;8(6):5765-73. doi: 10.1021/nn500583a. Epub 2014 May 20.

Edge structures for nanoscale graphene islands on Co(0001) surfaces.

ACS nano

Deborah Prezzi, Daejin Eom, Kwang T Rim, Hui Zhou, Shengxiong Xiao, Colin Nuckolls, Tony F Heinz, George W Flynn, Mark S Hybertsen

PMID: 24830340 DOI: 10.1021/nn500583a

Abstract

Low-temperature scanning tunneling microscopy measurements and first-principles calculations are employed to characterize edge structures observed for graphene nanoislands grown on the Co(0001) surface. Images of these nanostructures reveal straight well-ordered edges with zigzag orientation, which are characterized by a distinct peak at low bias in tunneling spectra. Density functional theory based calculations are used to discriminate between candidate edge structures. Several zigzag-oriented edge structures have lower formation energy than armchair-oriented edges. Of these, the lowest formation energy configurations are a zigzag and a Klein edge structure, each with the final carbon atom over the hollow site in the Co(0001) surface. In the absence of hydrogen, the interaction with the Co(0001) substrate plays a key role in stabilizing these edge structures and determines their local conformation and electronic properties. The calculated electronic properties for the low-energy edge structures are consistent with the measured scanning tunneling images.

Publication Types

• Journal Article
• Research Support, Non-U.S. Gov't
• Research Support, U.S. Gov't, Non-P.H.S.