STRUCTURE DETERMINATION OF THE SRTIO3(100) SURFACE

The surface of SrTiO3(100) was analysed by low energy electron diffraction. Intensity spectra were taken using a tv camera whose signal is evaluated under computer control. Model intensities were calculated fully dynamically for energies above 200 eV where details of the scattering potential are of minor influence. The best theory-experiment fit (Pendry R-factor = 0.53) shows the surface to be terminated by both Sr-O and O-Ti-O layers. The top layers are buckled by oxygen ions displaced out of the surface by 0.08 and 0.16 Å in the Ti and Sr terminated domains, respectively. The buckling, which creates a static dipole moment in the surface layer, is accompanied by a multilayer relaxation which for the first two layers is d12(Ti)/d0 = +2%, d23(Ti)/d0 = -2% for the Ti termination and d12(Sr)/d0 = -10%, d23(Sr)/d0 = +4% for the Sr terminated domains. © 1990 Pergamon Press plc.