First-principles studies of tip-sample interaction and STM-AFM image formation on TiO2(110)-1x1 and TiO2(110)-1x2 surfaces -: art. no. 125417

The tip-sample interaction and scanning tunneling microscopy atomic-force microscopy (STM-AFM) image formation on TiO2(110) 1x1 and 1x2 surfaces are simulated by using the ultrasoft pseudopotentials plane-wave technique. The effects of spin polarization and bias voltage on the tip-sample interaction in AFM are also investigated. The calculation demonstrates that overall the tip-oxygen interaction is much stronger than the tip-Ti interaction, which determines the main feature of the AFM image formation. The present calculations provide reasonable explanations to a very recent experiment adopting the technique of the combination of STM and AFM.