Transition from Reconstruction toward Thin Film on the (110) Surface of Strontium Titanate

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• 作者：Z. Wang ; A. Loon ; A. Subramanian ; S. Gerhold ; E. McDermott ; J. A. Enterkin ; M. Hieckel ; B. C. Russell ; R. J. Green ; A. Moewes ; J. Guo ; P. Blaha ; M. R. Castell ; U. Diebold ; L. D. Marks
• 刊名：Nano Letters
• 出版年：2016
• 出版时间：April 13, 2016
• 年：2016
• 卷：16
• 期：4
• 页码：2407-2412
• 全文大小：395K
• 年卷期：0
• ISSN：1530-6992

文摘

The surfaces of metal oxides often are reconstructed with a geometry and composition that is considerably different from a simple termination of the bulk. Such structures can also be viewed as ultrathin films, epitaxed on a substrate. Here, the reconstructions of the SrTiO₃ (110) surface are studied combining scanning tunneling microscopy (STM), transmission electron diffraction, and X-ray absorption spectroscopy (XAS), and analyzed with density functional theory calculations. Whereas SrTiO₃ (110) invariably terminates with an overlayer of titania, with increasing density its structure switches from n × 1 to 2 × n. At the same time the coordination of the Ti atoms changes from a network of corner-sharing tetrahedra to a double layer of edge-shared octahedra with bridging units of octahedrally coordinated strontium. This transition from the n × 1 to 2 × n reconstructions is a transition from a pseudomorphically stabilized tetrahedral network toward an octahedral titania thin film with stress-relief from octahedral strontia units at the surface.