Superstructures of carbon on V()
| Autor: | J. Redinger, Michael Schmid, Raimund Podloucky, Georg Kresse, C. Konvicka, Wolfgang Bergermayer, R. Koller, Peter Varga |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Low-energy electron diffraction
Ab initio chemistry.chemical_element Surfaces and Interfaces Condensed Matter Physics Surfaces Coatings and Films law.invention Crystallography chemistry law Ab initio quantum chemistry methods Atom Materials Chemistry Density functional theory Scanning tunneling microscope Carbon Superstructure (condensed matter) |
| Zdroj: | Surface Science. 497:294-304 |
| ISSN: | 0039-6028 |
| DOI: | 10.1016/s0039-6028(01)01659-4 |
| Popis: | Carbon adsorption on V(1 0 0) was studied by both experimental methods and density functional theory. At low carbon coverages of ΘC=0.18 ML and oxygen below the experimental detection limit, measured scanning tunneling microscopy (STM) images show both areas of local c(2×2) structure and 〈0 1 0〉 oriented rows of C atoms. At higher coverages of ΘC=0.41 ML, mainly 〈0 1 0〉 oriented C rows with some local p(1×2) patterns are formed. The observed c(2×2) pattern is attributed to the presence of oxygen, since a mixture of carbon and oxygen favors the c(2×2) superstructure according to both the STM and the ab initio results. The calculations show that for ΘC=0.50 ML the p(1×2) structure is more stable than c(2×2) by 0.13 eV per adsorbed atom. From the ab initio results it is predicted that p(1×2) changes into c(2×2) at a mixed coverage of about ΘC≈0.37 ML and ΘO≈0.13 ML. The geometry of the c(2×2) structure was determined using quantitative low energy electron diffraction showing good agreement with the ab initio data. Also the simulated STM images agree well with the experimental STM data. |
| Databáze: | OpenAIRE |
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