On the relationship between surface reconstructions and step edge stability on BaTiO3 (001)

The step orientations on four BaTiO3 (001) surfaces were quantified from scanning tunneling microscopy images in order to determine the relationship between surface reconstructions and step stability. The (1x1), c(2 x 2), (root 5 x root 5) R26.6 degrees, and (root 13 x root 13) R33.6 degrees surface reconstructions are compared. A well-known procedure that renders non-polar and low energy surface energies is applied to consider model step face structures, taking into account for the first time the adatoms of the surface reconstruction. A comparison of the number of steps with two crystallographically equivalent step face structures but different reconstruction termination shows that the surface adatoms affect the stability of steps. With the exception of the (1 x 1) surface, Ti adatoms influence the choice of crystallographic direction of the step edge in the surfaces mentioned above. (C) 2012 Elsevier B.V. All rights reserved.