Atomic Resolution Noncontact Atomic Force and Scanning Tunneling Microscopy of ${\mathrm{TiO}}_2\left(110\right)-(1\times 1)$ and - $(1\times 2)$: Simultaneous Imaging of Surface Structures and Electronic States

We present simultaneous imaging of ${\mathrm{TiO}}_2\left(110\right)-(1\times 1)$ and - $(1\times 2)$ 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 $(1\times 1)$ and in phase in $(1\times 2)$. 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 $(1\times 2)$, but reduced in $(1\times 1)$.