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O: Fachverband Oberflächenphysik

O 73: Nanostructures at Surfaces: Metals, Oxides and Semiconductors III

O 73.9: Vortrag

Mittwoch, 22. März 2017, 12:30–12:45, REC/PHY C213

Formation of CuO₂ chains embedded into the Ir(100) surface — •Lutz Hammer¹, Pascal Ferstl¹, Alexander Schneider¹, Florian Mittendorfer², and Josef Redinger² — ¹Solid State Physics, FAU Erlangen-Nürnberg — ²Applied Physics, TU Wien

We have investigated the oxidation of submonolayer deposits of copper on an Ir(100) surface by means of STM, quantitative LEED and DFT. Postoxidation of Cu deposits of 0.25 ML or less at temperatures around 800 K leads to the formation of regularly spaced, monatomic wires of twofold oxygen-coordinated Cu atoms. The Cu wires substitute Ir rows of the (100) terraces but are laterally shifted by half a surface unit vector with respect to the Ir positions and lifted up by 0.3 Å for steric reasons. They are flanked at both sides by rows of oxygen atoms being coordinated to one Cu and two Ir atoms each. Between the Cu oxide wires the Ir(100)2× 1-O superstructure develops in narrow stripes leading to a combined surface periodicity of n × 2 (or c(2n × 2)) with n = 4, 5, 6 ... depending on the initial Cu coverage. CuO₂ chains closer than fourfold Ir distance are not found which points towards a stabilization of the structure by the intermediate 2 × 1-O phase. Structural parameters derived from a LEED intensity analysis (R_P = 0.09) of the most dense phase (n = 4) coincide within a few picometers with the predictions of corresponding DFT model calculations.