Berlin 2018 – scientific programme

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O: Fachverband Oberflächenphysik

O 51: Poster: Electronic Structure of Surfaces: Spectroscopy, Surface States

O 51.5: Poster

Tuesday, March 13, 2018, 18:15–20:30, Poster B

Scattering at single, non-magnetic bulk impurities in Cu — •Thomas Kotzott, Henning Prüser, and Martin Wenderoth — IV. Physikalisches Institut - Solids and Nanostructures, Georg-August-Universität Göttingen, Germany

The scanning tunneling microscope is most commonly used as tool for surface science. However, making use of the electron focusing effect the STM can also give an insight into the solid and then reveals a powerful combination of atomic lateral resolution and probing bulk properties. Here, we investigate the scattering process of bulk electrons at single, non-magnetic impurities and compare the properties of Ge with Ag within a Cu crystal.

Dilute alloys of Ge/Ag in Cu are prepared in-situ under UHV conditions. Cu and the impurity material Ge/Ag are simultaneously evaporated from electron beam evaporators onto a single crystal Cu(100) surface. STM and STS was performed using a home-built low-temperature setup operating at 6 K and p < 5 · 10⁻¹¹ mbar.

Topography data reveals ring-like features in the local density of states with electronic contrasts down to few picometers in height. These signatures are attributed to the electrons being scattered at the impurity and propagating along the distinguished paths of electron focusing. Spectroscopy accesses the differential conductance with energy resolution and therefore resolves the scattering of different bulk states at the impurity. Comparing different non-magnetic impurities allows to expand the understanding of scattering processes on the atomic level.