Surface and subsurface alloy formation of vanadium on Pd(111)

Ch. Konvicka, Y. Jeanvoine*, E. Lundgren, G. Kresse*, M. Schmid, J. Hafner* and P. Varga

Institut für Allgemeine Physik, Technische Universität Wien, A-1040 Wien, Austria
*Institut für Materialphysik and Centre for Computational Materials Science, University of Vienna, Senseng. 8/12, A-1090 Wien, Austria

Surf. Sci. 463 (2000) 199-210

We have studied the submonolayer growth of vanadium on the Pd(111) surface at different substrate temperatures. By using LEIS (Low energy ion spectroscopy), AES (Auger electron spectroscopy), STM (Scanning tunneling microscopy), XPD (X-ray photoelectron diffraction) and ab-initio local-density-functional calculations we find that V atoms deposited at room temperature substitute surface Pd atoms. In addition, islands are formed on the surface, which consist mostly of the substituted Pd atoms. At higher temperatures, V diffuses into subsurface layers and at a temperature of 300 °C only a small amount of V is observed in the top-most layer. By using STM a (√3 × √3)R30° superstructure is observed to be formed and XPD measurements demonstrate that this structure is due to V atoms incorporated in the second layer. This finding is confirmed by ab-initio calculations. Further, a model for the (√3 × √3)R30° structure based on the experiments and the ab-initio calculations is given.

Corresponding author: P. Varga (varga< encoded email address >).

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