The structure of an α-Mo2C(0001) surface varies depending on the annealing temperature. At least 3 phases were observed by low energy electron diffraction. A well-ordered (√3 x √3)R30° structure was observed on α-Mo2C(0001) at annealing temperatures below 960K, which was imaged as a honeycomb structure by scanning tunnelling microscopy. A model was proposed for the C-terminated structure where C atoms were located on the threefold hollow sites of a Mo layer, and each carbon atom was observed as a depression of the honeycomb structure by scanning tunnelling microscopy. An increase in carbon coverage on the surface transformed the (√3 x √3)R30° structure to a c(2 x 4) structure where zig-zag rows running parallel to each other were observed by scanning tunnelling microscopy.

C-Terminated Reconstruction and C-Chain Structure on Mo2C(0001) Surface Studied by Low Energy Electron Diffraction and Scanning Tunnelling Microscopy. R.L.Lo, K.Fukui, S.Otani, S.T.Oyama, Y.Iwasawa: Japanese Journal of Applied Physics, 1999, 38, 3813-5