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Combined STM, LEED and DFT study of Ag(1 0 0) exposed to oxygen near atmospheric pressures |
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| Authors: | I Costina H Schiechl A Stierle S Kumaragurubaran J Hafner P Varga |
| Institution: | a Max-Planck Institut für Metallforschung, Heisenbergstrasse 3, D-70569 Stuttgart, Germany b Institut für Allgemeine Physik, Technische Universität Wien, A-1040 Wien, Austria c Institut für Materialphysik and Center for Computational Materials Science Universität Wien, Sensengasse 8/12, A-1090 Wien, Austria |
| Abstract: | We have investigated the interaction of molecular oxygen with the Ag(1 0 0) surface in a temperature range from 130 K to 470 K and an oxygen partial pressure ranging up to 10 mbar by scanning tunneling microscopy, low electron energy diffraction, Auger electron spectroscopy and ab initio density functional calculations. We find that at 130 K, following oxygen exposures of 6000 Langmuirs O2, the individual oxygen atoms are randomly distributed on the surface. When the sample is exposed to 10 mbar O2 at room temperature, small, p(2 × 2) reconstructed patches are formed on the surface. After oxidation at ≈470 K and 10 mbar O2 pressure the surface undergoes a c(4 × 6) reconstruction coexisting with a (6 × 6) superstructure. By ab initio thermodynamic calculations it is shown that the c(4 × 6) reconstruction is an oxygen adsorption induced superstructure which is thermodynamically stable for an intermediate range of oxygen chemical potential. |
| Keywords: | Oxidation Surface relaxation and reconstruction Scanning tunneling microscopy Low energy electron diffraction Density functional calculations |
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