Fig. 3.

Stepwise annealing of ${\mathrm{T}\mathrm{i}\mathrm{O}}_2$(110) with a close-to-saturation coverage of ${\mathrm{O}}_2$ dosed at 80 K. (A–C) AFM images (taken at 80 K) after annealing to a temperature of (A) 160 K, (B) 220 K, and (C) room temperature (RT). The adsorbed species are marked with the same colors and symbols as in Fig. 1, with one red rectangle in C marking a pair of O adatoms (2$\times {\mathrm{O}}_{\mathrm{a}\mathrm{d}}$). Inset in C is an AFM image of the white rectangle imaged closer to the surface, showing an empty ${\mathrm{V}}_{\mathrm{O}}$ more clearly. (D) Number of adsorbed species $N\left(\text{x}\right)|\text{x}\in \left\{\omega ,\pi +\tau ,{\mathrm{O}}_{\mathrm{a}\mathrm{d}}\right\}$ at each annealing temperature. Both columns are normalized to the number of (empty and filled) oxygen vacancies $N$(${\mathrm{V}}_{\mathrm{O}}$) on the surface.