  Horizontal shifts in the top layer of highly oriented pyrolytic graphite,
induced by a scanning tunneling microscope (STM) tip, are presented. Excellent
agreement is found between STM images and those simulated using density
functional theory. First-principle calculations identify that the low-energy
barrier direction of the top layer displacement is toward a structure where
none of the carbon pz orbitals overlap, while the high-energy barrier direction
is toward AA stacking. Each directional shift yields a real-space surface
charge density similar to graphene; however the low-energy barrier direction
requires only one bond length to convert ABA (Bernal) to ABC (rhombohedral).
