Scanning tunneling microscopy/spectroscopy study of point defects on TiO2(110)-(1 x 1) surface

The electronic structure around a point defect in an annealed TiO2 (110)-(1 x 1) surface has been studied by scanning tunneling microscopy/spectroscopy. At a defect site of bridging oxygen, we found an unoccupied defect state at 1.2 eV above the Fermi level. Trapped electrons at the gap states were found on fivefold-coordinated titanium ion rows by current imaging tunneling spectroscopy, We calculated the electronic states of an oxygen defect by the spin-polarized discrete variational (DV)-X alpha method using a cluster model. The calculated defect states are in good agreement with the experimental results.