Atomic resolution noncontact atomic force and scanning tunneling microscopy of TiO2(110)-(1x1) and -(1x2):: Simultaneous imaging of surface structures and electronic states

We present simultaneous imaging of TiO2(110)-(1 x I) and -(1 x 2) using noncontact atomic force microscopy (NC-AFM) and scanning tunneling microscopy (STM). The surface topography was imaged under NC-AFM feedback. while the surface electronic states were imaged by STM. The image contrasts of NC-AFM and STM were antiphase in (1 X 1) and in phase in (1 x 2). The uppermost oxygen and Ti atoms underneath were, respectively, imaged by NC-AFM and STM. The NC-AFM image contrast was close to the true surface topography in (1 x 2), but reduced in (1 x 1).