Influence of impurities on localized transition metal surface states: scanning tunneling spectroscopy on V(001)

M.M.J. Bischoff1, C. Konvicka2, A.J. Quinn1, M. Schmid2, J. Redinger3, R. Podloucky4, P. Varga2, H. van Kempen1

1 Research Institute for Materials, University of Nijmegen, NL-6525 ED Nijmegen, the Netherlands,
2 Institut für Allgemeine Physik, Technische Universität Wien, A-1040 Wien, Austria
3 Institut für Technische Elektrochemie and Center for Computational Materials Science, Technische Universität Wien, A-1060 Wien, Austria
4 Institut für Physikalische Chemie and Center for Computational Materials Science, Universität Wien, A-1090 Wien, Austria

Phys. Rev. Lett. 86 (2001) 2396-2399

The first scanning tunneling spectroscopy measurements on V(001) are reported. A strong surface state is detected which is very sensitive to the presence of segregated carbon impurities. The surface state energy shifts from 0.03 eV below the Fermi level at clean areas towards higher energies (up to ~ 0.2 eV) at contaminated areas. Because of the negative dispersion of this state, the upward shift cannot be described in a simple confinement picture. Rather, the surface state energy is governed by vanadium surface s-d interactions which are altered by carbon coverage.

Corresponding author: H. van Kempen. Reprints also available from M. Schmid (schmid< encoded email address >).

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