Preparation of a pristine TiO2 anatase (101) surface by cleaving

A natural TiO2 anatase crystal, cut to exhibit its (010) surface, was cleaved by breaking off one of its corners. The resulting sample exhibited a small, flat area ca. 2 mm(2) in size with a (101) orientation as confirmed by LEED. The evolution of the surface morphology was monitored with UHV-STM. After one sputtering/annealing cycle the surface is characterized by periodic ridges that run parallel to the [010] direction. The ridges are ∼ 3 nm high and 10-15 nm wide and have a spacing of 30 nm. Interestingly, [Formula: see text]-oriented step edges are not observed, despite them having the lowest formation energy. The ridges flatten with repeated sputter/annealing cycles. After a total of three cycles a flat surface is achieved, which exhibits trapezoidal terraces that are typical for anatase (101). The importance of preparing such a pristine surface for understanding the surface structure and chemistry of TiO2 anatase is discussed.