Atomic Imaging Across Strain Boundaries in Bilayer Graphene with ADF-STEM and DF-TEM

Bilayer graphene possesses two degenerate lowest energy configurations which are geometrically mirrored—AB and BA stacking[1]. Both stacking geometries have been observed as domains in bilayer systems grown by chemical vapor deposition[2]. Here we examine the structure at the interfaces of stacking domains using atomic-resolution scanning transmission electron microscopy (STEM) and standard dark-field TEM[3]. We find that domain boundaries are formed by a continuous strain between layers with a displacement direction and magnitude quantized by the bilayer energy landscape. The strained interfaces between stacking domains are often microns in length and have been predicted to contain unique electronic properties[4].