Visualization of a Maze-Like Reconstruction of Graphene on a Copper Surface at the Atomic Scale

Interaction with the substrate plays an essential role in determining the structure and electronic property of graphene supported by a surface. We observe a maze-like reconstruction pattern in graphene on flat copper foil. With functionalized scanning tunneling microscope tips, a triangular three-for-six structure of graphene and a mixed (2√2 ×√2 )R45° reconstruction of a Cu(100) surface are separately visualized at the atomic scale. Substrate-induced changes in the structure and electronic property are further illustrated by micro-Raman spectroscopy and scanning tunneling spectroscopy. This finding suggests a new method to effectively induce partial sp³ hybridization in a single-layer graphene and therefore to tune its electronic property through interaction with the substrate.