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Structural and electronic properties of graphite and graphite intercalation compounds MC[sub 8] (M = K, Rb, Cs) governing their scanning tunneling microscopy images

Journal Article · · Journal of Physical Chemistry; (United States)
DOI:https://doi.org/10.1021/j100082a034· OSTI ID:6914856
; ;  [1]; ;  [2]
  1. North Carolina State Univ., Raleigh, NC (United States)
  2. Albert-Ludwigs Univ., Freiburg (Germany)

Several puzzling observations in the scanning tunneling microscopy (STM) and atomic force microscopy (AFM) studies of highly oriented pyrolytic graphite (HOPG) and its intercalation compounds MC[sub 8] (M = K, Rb, Cs) were investigated on the basis of atom-atom potential and Coulombic interaction energy calculations. The charge or spin density wave state of a graphite monolayer is found inconsistent with an identical peak registry of the HOPG STM images obtained at plus and minus bias voltages. Simultaneous STM/AFM measurements of HOPG show the STM and AFM images to have an identical peak registry, which implies that the local hardness of the surface monolayer is larger at the B-site than at the A-site. We confirm this implication by estimating the local hardness in the surface monolayer of a graphite bilayer in terms of atom-atom potential calculations. The essential characteristics of the Moire STM images of HOPG are correctly predicted by the local hardness map obtained for the surface monolayer of a graphite bilayer in terms of atom-atom potential calculations. This supports the notion that the tip-force-induced topography change in the surface monolayer is generally responsible for Moire STM patterns in layered materials. 29 refs., 5 figs., 2 tabs.

DOE Contract Number:
FG05-86ER45259
OSTI ID:
6914856
Journal Information:
Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 98:31; ISSN JPCHAX; ISSN 0022-3654
Country of Publication:
United States
Language:
English