GIANT AND SUPERGIANT LATTICES ON GRAPHITE

Anomalous giant lattices have been observed on four separate samples o f highly oriented pyrolytic graphite with scanning tunneling microscop y. They exhibit hexagonal symmetry with lattice constants of 1.7, 2.8, 3.8, and 6.6 nm. Atomic resolution of graphite was obtained simultane ously. Kuwabara, Clarke, and Smith [Appl. Phys. Lett. 56, 2396 (1990)] have suggested that those superperiodic features may be Moire pattern s due to rotational misorientation of the top layer relative to the un derlying graphite single crystal. In this paper we present (1) evidenc e for the misorientation of the graphite top layer which causes the ob served giant lattices, (2) a complete description to account for detai led features of these giant lattices, (3) observation of a supergiant lattice superimposed on the atomic and giant lattices, and (4) adsorpt ion of cobalt particles on the giant lattice.