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O: Oberflächenphysik

O 19: Electronic structure II

O 19.1: Vortrag

Dienstag, 28. März 2006, 11:15–11:30, WIL A317

Surface state lifetimes from scanning tunnelling spectroscopy: A theoretical analysis — •Michael Becker¹, Simon Crampin², and Richard Berndt¹ — ¹Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany — ²Department of Physics, University of Bath, Bath BA2 7AY, United Kingdom

Recently the discrepancy between image state lifetimes measured by means of the scanning tunneling microscope (STM) and two-photon-photoemission spectroscopy was lifted [1]. The electric field applied in STM was shown to cause an increase in both the efficiency of the image state decay channels as well as their number. In the light of this work, we theoretically investigate the impact of the STM induced electric field on the inelastic electron-electron damping rate of the electron- and hole-like excitations in the Shockley surface state band at Ag(111). Our calculations within the GW approximation of many-body theory are based upon the approach developed by Chulkov and coworkers [2]. The results indicate that under typical tunnelling conditions the STM does not significantly alter the surface state wavefunction and so previous STM derived Shockley state lifetimes need not be corrected.

[1] S. Crampin, Phys. Rev. Lett. 95, 046801 (2005)

[2] E. V. Chulkov, I. Sarria, V. M. Silkin, J. M. Pitarke, and P. M. Echenique, Phys. Rev. Lett. 80, 4947 (1998)