Surface structure of SrTiO3(1 0 0)

Atomic and electronic structures of the SrTiO3(1 0 0) surface have been studied by using scanning tunneling microscopy (STM). We observed the c(4 × 2) (θ=0.25) phase and the series of the structural phase transitions, e.g., c(2 × 2) (θ=0.5) → c(4 × 4) (θ=0.375) → 2 × 2 (θ=0.25) → c(4 × 4) (θ=0.125) → 4 × 4 (θ=0.0625) → disorder → (5×5)-R26.6° (θ=0.2) → (13×13)-R33.7° (θ=0.0769). For the SrTiO3(1 0 0) surface reconstructions, Sr adatom model, consisting of ordered Sr adatoms at the oxygen fourfold sites of a TiO2-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.