Figure 2

Surface periodicity of the monoclinic \((20\bar{1})\) surface. An enlarged \((1\times 2)\) periodicity is expected with respect to the rutile (001) surface. Crystallographic (shaded blue) und surface unit cells (yellow) are highlighted in (a) the top view onto the monoclinic \((20\bar{1})_\text{M}\)/rutile \((001)_\text{R}\) surface, cross sections of (b) the \((010)_\text{M}/(100)_\text{R}\) and (c) the \((001)_\text{M}/(010)_\text{R}\) plane illustrate the monoclinic cell dimensions. The dashed rectangles outline a rutile cell. The sketch on the left indicates the respective lines of sight. The crystal structures were visualized by the open source software Vesta 3.4.7 (http://jp-minerals.org/vesta/en/)²⁴.