Full text loading...
(Color online) (a) NC-AFM in UHV and height cross section showing the presence of small islands high on the top of nominal terminated STO(100) surface. (b) AFM image (, contact mode in air) of nominal SrO terminated STO(100) surfaces. (c) Surface structural model used to fit the experimental GIXD data using the ROD program consisting of a mixed terminated (on the left side) and SrO (on the right side) surfaces. The labels for the atoms correspond to the ones used to identify them in Table II. An oxygen overlayer covering the layer and composed by two different sublattices [O(0) and ] is also considered.
(Color online) Comparison between the nominal terminated T1 (black symbols) and SrO terminated S1 (red symbols) surfaces for selected CTRs. The continuous lines are theoretical fits to model II. For S1 the blue curve is a fit using model I. On the top of the figures a simple sketch of the distribution of the layers as a result of the structural refinement is shown for S1 (on the left) and T1 (on the right) samples.
(Color online) Experimental CTRs and fitted curves according to model II (continuous lines) on a logarithmic scale. (a) Samples T2 (black) and T3 (red) and (b) samples S1 (black) and S2 (red). The black and red curves are shifted one unity, as indicated in the figure, for clarity.
Schematic description of the five surfaces studied and of the preparation methods: (a) Chemically etched and annealed in furnace at in flowing , (b) T1, plus UHV annealing at , (c) T1, plus annealig in of flowing at , (d) film deposition by PLD on a T1 surface, are (e) S1, plus annealing in of flowing at . In the last two columns, the reduced from the final refined model, model II, is shown.
Relative ratio (in percent) between the topmost surface layers and surface normal displacements of atoms from the bulk positions [see Fig. 1(c)] given normalized to the STO lattice constant (in relative units). The average error bar is with exception of some oxygen ions marked with a star, where the error can be as large as 50% mainly due to the low occupancy. T1, T2, and T3 samples have an additional disordered oxygen overlayer, 50% occupied as indicated in the text. In S1 and S2, a 100% surface occupancy is achieved in four atomic levels instead of two. The numbers in brackets are then the fraction of layers exposed following the sequence : common layer.
Article metrics loading...