Identification of Twinning-induced Edges on the Cleaved Graphite Crystal Surface

Edges on the cleaved graphite crystal surface were found to be preferentially oriented perpendicularly to the hexagonal perimeter facet of the graphite single crystal assigned to the zig-zag-type edge. The crystal orientation was determined by observing the Brillouin zone in the photoelectron angular distribution of the valence band. Straight edges seen on the cleavage plane were aligned along the armchair atomic arrangement direction. These features were revealed to be formed at the twinned domain boundaries along the [1120] direction.