Extended vacuum annealing of rutile (110) produced macroscopic and nanoscopic changes in the surface morphology. These resulted from ordering of the O vacancies and Tin+ interstitials, in the bulk, into crystallographic shear planes. Low-energy electron diffraction and scanning tunnelling microscopy were used to identify the surface termination of crystallographic shear planes which were produced in the bulk. The directions of the planar defects along the surface indicated that the {132} series of shear planes dominated the scanning tunnelling microscopic images, as confirmed by the low-energy electron diffraction results. The spacing between planes gradually varied across the surface, suggesting that a series of Magnéli phases had formed. The low-energy electron diffraction patterns confirmed the coexistence of relatively large areas of single phase, and a continuum of separations between the planes. The formation of crystallographic shear planes also led to extensive faceting of the crystal. This was visible, to the unaided eye, as a rippled surface finish. Some Ca segregation was observed during plane formation. However, when removed, the crystallographic shear planes remained; thus indicating that they were not significantly stabilized by the Ca.

STM and LEED Observations of the Surface Structure of TiO2(110) Following Crystallographic Shear Plane Formation. Bennett, R.A., Poulston, S., Stone, P., Bowker, M.: Physical Review B, 1999, 59[15], 10341-6