Transition from order to configurational disorder for surface reconstructions on SrTiO 3(111)
Ann C. Chiaramonti Debay, Laurence D. Marks , Shams Rahman, Martin Castell
There is growing interest in oxide surfaces due to their role in areas ranging from the growth of oxides for low power electronics to heterogeneous catalysis. However, there are still many uncertainties about their atomic structure although substantial progress has been made particularly for the strontium titanate (001) and (110) surfaces. We report here the structure of three members of the (111) nxn (n=2-4) reconstructions using a combination of transmission electron diffraction, density functional theory modelling, scanning tunneling microscopy and aberration-corrected high resolution electron microscopy. The surface contains a mixture of the same tetrahedral TiO4 units found on the (110) surface over the top of octahedral TiO5 and TiO6 units in the second layer which are similar to the (001) surface. The scanning tunneling images indicate that the structure can either be ordered into nxn units or can form a glass-like structure.