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O: Fachverband Oberflächenphysik

O 56: Oxide Surfaces I

O 56.2: Vortrag

Mittwoch, 13. März 2013, 16:15–16:30, H45

Reversible transitions between surface reconstructions on SrTiO3 — •Stefan Gerhold, Zhiming Wang, Xianfeng Hao, Michael Schmid, and Ulrike Diebold — Institute of Applied Physics, TU Wien, Austria

SrTiO₃ as an archetypical perovskite oxide has attracted intense interest in diverse fields ranging from fundamental solid-state physics and chemistry, materials science to electronics applications. In all these applications, the surface properties are of vital importance. We study the evolution of surface reconstructions on the SrTiO₃(110) and (001) surface using STM, LEED, XPS and ISS. Atomically well-defined SrTiO₃(110) surfaces can be obtained by Ar⁺ sputtering and annealing. Mono-phased reconstructions are obtained, and can be transformed into each other reversibly by depositing Sr or Ti followed by annealing. The most commonly-observed SrTiO₃(110) (4 × 1) reconstruction consists of a layer of TiO₄ tetrahedra, which forms a network of six- and ten-membered rings by corner-sharing oxygen atoms. The mirror symmetry in the six-membered rings is broken along the [1-10] direction, therefore two degenerate anti-parallel (4 × 1) domains are formed. Two types of vacancies are present at domain boundaries. These can be tuned by adjusting the oxygen pressure during annealing; depending on the type of domain boundary different band bending is observed. At the SrTiO₃(001) surface a reversible change between c(4 × 2), (2 × 2), (1 × 1), and c(2 × 2) reconstructions can also be achieved by evaporating Sr or Ti followed by annealing. This work was supported by the Austrian Science Fund (project F45).