Stacking domains of epitaxial few-layer graphene on SiC(0001)

We used low-energy electron microscopy (LEEM) and scanning tunneling microscopy (STM) to investigate domain structures of epitaxial few-layer graphene grown on SiC(0001). Dark-field (DF) LEEM images formed using (10) and (01) beams clearly indicate that bilayer graphene consists of two types of domains, which have threefold symmetry and are rotated by 180 degrees with respect to each other. The DF LEEM images show clear domain contrasts at energies where (10)- and (01)-beam intensities calculated for bulk graphite are largely different. This means that the two types of domains are different in stacking: AB and AC stackings. The stacking domains are also supported by the STM images of bilayer graphene showing both hexagonal and honeycomb patterns.