Direct Imaging of Reconstructed Atoms on TiO₂ (110) Surfaces

• Published in: Science (American Association for the Advancement of Science) Vol. 322; no. 5901; pp. 570 - 573
• Main Authors: Shibata, N, Goto, A, Choi, S.-Y, Mizoguchi, T, Findlay, S.D, Yamamoto, T, Ikuhara, Y
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 24.10.2008; The American Association for the Advancement of Science
• Subjects: Atomic structure; Atoms; Atoms & subatomic particles; Chemical engineering; Condensed matter: structure, mechanical and thermal properties; Electron irradiation; Electron microscopes; Exact sciences and technology; Image contrast; Image reconstruction; Imaging; Materials; Materials science; Octahedrons; Oxides; Physics; Scientific imaging; Solid surfaces and solid-solid interfaces; Surface structure and topography; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Technology; Dangling bonds; Surface reconstruction; Surface termination; Image resolution; Inorganic compounds; Transmission electron microscopy; Imaging; Transition element compounds; Titanium oxide; Atomic structure; Surface structure
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1165044

Determining the atomic structures of oxide surfaces is critical for understanding their physical and chemical properties but also challenging because the breaking of atomic bonds in the formation of the surface termination can involve complex reconstructions. We used advanced transmission electron microscopy to directly observe the atomic structure of reduced titania (TiO₂) (110) surfaces from directions parallel to the surface. In our direct atomic-resolution images, reconstructed titanium atoms at the top surface layer are clearly imaged and are found to occupy the interstitial sites of the TiO₂ structure. Combining observations from two orthogonal directions, the three-dimensional positioning of the Ti interstitials is identified at atomic dimensions and allows a resolution of two previous models that differ in their oxygen stoichiometries.