Berlin 2008 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 50: Symposium: Surface Spectroscopy on Kondo Systems II (Invited Speakers: Jonathan Denlinger, Johann Kroha, Alexander Schneider)

O 50.6: Vortrag

Mittwoch, 27. Februar 2008, 17:15–17:30, HE 101

Kondo effect of subsurface Fe and Co impurities in Cu(100) - a comparative STS study — •Alexander Weismann, Martin Wenderoth, Henning Prüser, and Rainer G. Ulbrich — IV. Physikalisches Institut; Georg-August Universität Göttingen, Germany

We prepared single isolated subsurface iron and cobalt atoms beneath the Cu(100) surface by co-deposition of host metal and impurity compound under UHV conditions. The STM topographies at 6K show bulk state LDOS oscillations with four-fold symmetry in the vicinity of the defects. The observed patterns are in good agreement with the results of calculations based on host metals Greens function. This allows a depth classification and an extraction of the Kondo-related scattering phase from the STM experiment. In STS measurements both species of impurities show characteristic Kondo features on distinctly different energy scales. The dI/dV spectra show Fano line shapes depending on depth of the impurity below the surface. In the case of Fe the observed resonance width is extremely narrow so that even in the topographies a significant change of the interference pattern within +/- 3mV around zero bias can be observed. This work was supported by DFG SFB 602 TPA3.