Understanding image contrast formation in TiO.sub.2./sub. with force spectroscopy

0386566 - FZÚ 2013 RIV US eng J - Journal Article
Yurtsever, A. - Fernandez-Torre, D. - González, C. - Jelínek, Pavel - Pou, P. - Sugimoto, Y. - Abe, M. - Pérez, R. - Morita, S.
Understanding image contrast formation in TiO₂ with force spectroscopy.
Physical Review. B. Roč. 85, č. 12 (2012), "125416-1"-"125416-9". ISSN 1098-0121
R&D Projects: GA MŠMT(CZ) ME10076
Institutional research plan: CEZ:AV0Z10100521
Keywords : DFT * AFM * force spectroscopy * atomic resolution
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 3.767, year: 2012

Site-specific force measurements on a rutile TiO2(110) surface are combined with first-principles calculations in order to clarify the origin of the force contrast and to characterize the tip structures responsible for the two most common imaging modes. Our force data, collected over a broad range of distances, are only consistent with a tip apex contaminated with clusters of surface material. A flexible model tip terminated with an oxygen explains the protrusion mode. For the hole mode we rule out previously proposed Ti-terminated tips, pointing instead to a chemically inert, OH-terminated apex. These two tips, just differing in the terminal H, provide a natural explanation for the frequent contrast changes found in the experiments. As tip-sample contact is difficult to avoid while imaging oxide surfaces, we expect our tip models to be relevant to interpret scanning probe studies of defects and adsorbates on TiO2 and other technologically relevant metal oxides.
Permanent Link: http://hdl.handle.net/11104/0215860