Scanning tunneling microscopy of Kish graphite and highly oriented pyrolytic graphite in air

Abstract
The atomic images of single‐crystal graphite (Kish graphite) in air were compared with those of highly oriented pyrolytic graphite (HOPG) using a scanning tunneling microscope. In the usual topography mode, the Kish graphite showed an anomalous atomic corrugation ΔZ up to 175 Å, larger than that of HOPG, whereas both the atomic corrugations in Kish graphite and HOPG increased with decreasing tunnel resistance RT. On the other hand, in a (variable) current mode, the Kish graphite showed a ratio of the tunneling current modulation ΔIT/〈IT〉 several times smaller than that of HOPG, while both the current modulations in Kish graphite and HOPG were nearly independent of the tunnel resistance RT in contrast to the atomic corrugation.