Surface relaxation of SrTiO3(001)

Surface X-ray diffraction has been used to examine the 300 K structure of SrTiO3(001) 1 x 1 with a termination of 78% TiO and 22% SrO. The data indicate that a lateral ferroelectric distortion is absent on both terminations, consistent with a recent theoretical calculation. Although the negligible Ti atom relaxation found on the TiO termination is consistent with medium-energy ion scattering data, it differs from recent density functional theory calculations by 0.13 and 0.16 Angstrom. Zn contrast, the Sr displacement towards the SrO surface of 0.22 +/- 0.07 Angstrom is in good agreement with theory. (C) 2000 Elsevier Science B.V, All rights reserved.