Lateral Distribution of Li Atoms at the Initial Stage of Adsorption on TiO2(110) Surface

Adsorption of Li atoms on a titanium dioxide (TiO2) (110)-(1x1) surface was examined by a scanning tunneling microscope (STM). Lithium adatoms were observed as protrusions in empty state images. Three different adsorption sites for Li atoms, a 4-fold hollow site of in-plane O atoms, a 3-fold hollow site composed of one bridging O atom and two in-plane O atoms, and a bridging O vacancy, were identified. The Li adatoms were placed predominantly on the 4-fold hollow site. Time-lapse STM observation revealed that the Li adatoms at the three sites were mobile at room temperature. The number density of the Li adatoms on the terraces was reduced around the steps, which was attributed to the perturbation of the surface electronic state by the Li adatoms concentrated at the steps.