Electronic and structural properties of armchair SWCNT/TiO2(110)-(1 x 2) system

We have presented structural and electronic properties of single-walled carbon nanotubes (CNTs) with armchair chirality on the reconstructed rutile TiO2(110)-(1 x 2) surface by means of ab initio calculations using density functional theory. For the TiO2 surface reconstruction, we have adopted an added-row model which was experimentally proposed in parallel to STM patterns and theoretically agreed by first principle calculations. In this work, we have studied, as examples, two CNTs with different sizes, (3,3) and (6,6), and their adsorption on this surface. The CNTs are observed not to chemisorb on the reconstructed rutile surface with added-rows, however, when it is further reduced, i.e., on the added-row model with the two topmost bridging oxygens removed, we obtained significant binding for the tubes through Ti-C bonds. We have also determined the band structures and the charge densities to discuss the effects and contributions of nanotubes to the gap states. (C) 2010 Elsevier B.V. All rights reserved.