The surface was studied by using a new atomic force microscope. It was found that the surface structures of the (100), (110) and (111) planes were different to that of the bulk, although the surface structures of (100) and (110) were still strongly affected by the bulk. The surface structure of the (110) plane was quite similar to the atomic arrangement of the (100) plane; which was the most stable one with regard to the surface energy. Line defects were found on each plane, and the surface structure of the (111) plane was more irregular than those of (100) or (110). Bright spots in the atomic force microscopic images corresponded to the locations of O atoms. Interactions between O on the surface, and Mg or O on the second layer, affected the crystallographic orientation dependence of the wettability of MgO single crystal by liquid metals.

H.Takeda, M.Takeda, K.Nogi, K.Ogino: Materials Transactions, 1994, 35[7], 466-72