Dresden 2017 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 17: Scanning Probe Techniques: Method Development II

O 17.7: Vortrag

Montag, 20. März 2017, 17:15–17:30, TRE Phy

HR-LC-AFM for detection of current paths on oxides with atomic resolution — •Christian Rodenbücher, Gustav Bihlmayer, Marcin Wojtyniak, Wolfgang Speier, and Kristof Szot — Peter-Grünberg-Institut and JARA-FIT, Forschungszentrum Jülich, 52425 Jülich

The ongoing miniaturization of electronic devices and the introduction of novel materials such as metal oxides for memristive applications is accompanied with new challenges since the electronic transport phenomena have to be analyzed on the atomic scale. Typically, the STM method is used to obtain information about the electronic properties in nanoscale, however it cannot be successfully applied on all surfaces. For example, on surfaces with inhomogeneous conductivity any changes in the electrical properties of the surface are inseparable from changes in the sample topography. Hence, we implemented the technique of high-resolution local-conductivity atomic force microscopy (HR-LC-AFM) for the investigation of oxide surfaces and achieved, for a first time, a direct current mapping with atomic resolution. We revealed that the surface conductivity of the prototypical transition metal oxides SrTiO₃ and TiO₂ is confined to conducting areas on the nanoscale. Assisted by ab initio theory we argue that a clustering of oxygen vacancies in the surface of transition metal oxides could be responsible for the observed localization. This way we introduced LC-AFM as next scanning probe tool with true atomic resolution complementing the well-established techniques of (NC-)AFM, FFM, SKPM, and STM which may help to open up a new chapter on surface science.