Regensburg 2019 – scientific programme

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O: Fachverband Oberflächenphysik

O 88: Electronic Structure of Surfaces II

O 88.8: Talk

Thursday, April 4, 2019, 16:45–17:00, H26

STM investigation of scattering phase shifts of single non-magnetic impurity atoms buried in Cu — •Thomas Kotzott¹, Mohammed Bouhassoune², Henning Prüser¹, Samir Lounis², and Martin Wenderoth¹ — ¹IV. Physikalisches Institut, Georg-August-Universität Göttingen, Germany — ²Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich & JARA, Germany

Impurities in nanostructures can be crucial for the functionality of the devices. Hence, scattering properties of impurity atoms in metals have been thoroughly investigated in the past by theoretical calculations and experimental measurements of the bulk. Here, we present a study to characterize the scattering phase of single, non-magnetic atoms buried in Cu by means of scanning tunneling microscopy (STM) and density functional theory. Using the electron focusing effect we visualize single Ge and Ag atoms several layers below the Cu surface. Experiments have been performed with a home-built low-temperature UHV-STM operating at 6K. Dilute alloys were grown by co-deposition of Cu and Ag or Ge, respectively, onto a clean Cu(100) surface. Ab-initio calculations and a plane-wave toy model are compared to the data.

We can extract the phase shift from the LDOS pattern above bulk impurities which is set by depth and species of the impurity. We find that the simple model of a Lorentzian scatterer is not sufficient for understanding all the characteristics on the local scale for a non-magnetic atom. This work was supported by DFG projects LO 1659/5-1 and WE 1889/8-1.