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

Abstract

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 $180\ifmmode^\circ\else\textdegree\fi{}$ 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.