Limits of perturbation theory: first principles simulations of scanning tunneling microscopy scans on Fe(100)

W.A. Hofer1, J. Redinger1, A. Biedermann2 and P. Varga2

1Center for Computational Materials Science, Getreidemarkt 9/158, Technische Universität Wien, A-1060 Wien, Austria
2Institut für Allgemeine Physik, Technische Universität Wien, A-1040 Wien, Austria

Surf. Sci. 466 (2000) L795-L801

Scanning tunneling microscopy (STM) scans on Fe(100) are compared with first principles calculations of the tunneling current based on the transfer Hamiltonian method. Experimentally, we find a reversal of corrugation for separations between sample and tip below 400 pm. In the simulations we can reproduce these topographies only in a distance range above 400 pm. The approach therefore fails to describe the observed corrugation reversal. We suggest that this failure is due to the quenching of surface states by the approaching STM tip.

Corresponding author: W.A. Hofer. Reprints also available from P. Varga (varga< encoded email address >).

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