▎ 摘　　要

Large-area bilayer graphene (BG) is grown epitaxially on Ru(0001) surface and characterized by low temperature scanning tunneling microscopy. The lattice of the bottom layer of BG is stretched by 1.2%, while strain is absent from the top layer. The lattice mismatch between the two layers leads to the formation of a moire pattern with a periodicity of similar to 21.5 nm and a mixture of AA-and AB-stacking. The root 3 x root 3 superstructure around atomic defects is attributed to the inter-valley scattering of the delocalized p-electrons, demonstrating that the as-grown BG behaves like intrinsic free-standing graphene. (C) 2014 AIP Publishing LLC.