GIANT AND SUPERGIANT LATTICES ON GRAPHITE

Anomalous giant lattices have been observed on four separate samples of highly oriented pyrolytic graphite with scanning tunneling microscopy. They exhibit hexagonal symmetry with lattice constants of 1.7, 2.8, 3.8, and 6.6 nm. Atomic resolution of graphite was obtained simultaneously. Kuwabara, Clarke, and Smith [Appl. Phys. Lett. 56, 2396 (1990)] have suggested that those superperiodic features may be Moire patterns due to rotational misorientation of the top layer relative to the underlying graphite single crystal. In this paper we present (1) evidence for the misorientation of the graphite top layer which causes the observed giant lattices, (2) a complete description to account for detailed features of these giant lattices, (3) observation of a supergiant lattice superimposed on the atomic and giant lattices, and (4) adsorption of cobalt particles on the giant lattice.