SURFACE-STRUCTURES OF MGO(100) AND SRTIO3(100) AS REVEALED BY ATOMIC-FORCE MICROSCOPY

We have investigated surface structures of MgO(100) and SrTiO3(100) by atomic force microscopy. Atomically flat terraces separated by monato mic height steps could be obtained on the freshly cleaved MgO(100) sur faces. We have observed an atomic structure indicating a bulk terminat ed (1 X 1) structure on the terraces. We have found that nanocrystals, which might be an indication of the surface roughening, were formed o n the MgO(100) surfaces after O-2 annealing. For SrTiO3(100), we have clarified that the step-terrace structure was obtained by O-2 annealin g at 1100 K. Annealing at 1300 K, however, resulted in morphology chan ges from flat to rough and non-faceted surfaces.