Surface structure of SrTiO3(100)

Atomic and electronic structures of the SrTiO3(100) surface have been studied by using scanning tunneling microscopy (STM). We observed the c(4 x 2) (theta = 0.25) phase and the series of the structural phase transitions, e.g., c(2x2) (theta = 0.5) --> c(4x4) (theta = 0.375) --> 2x2 (theta = 0.25) --> c(4x4) (theta = 0.125) --> 4x4 (theta = 0.0625) disorder --> (root5 x root5)-R26.6degrees (theta = 0.2) --> (root13 x root13)-R33.7degrees (theta = 0.0769). For the SrTiO3(100) surface reconstructions, Sr adatom model, consisting of ordered Sr adatoms at the oxygen fourfold sites of a TiPO2-terminated layer, can explain the experimental results very well. We theoretically simulated the model clusters with the first-principles total-energy calculation. Calculated density of states and images for STM are in good agreement with the experimental results. (C) 2003 Elsevier B.V. All rights reserved.