Dresden 2020 – wissenschaftliches Programm
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O 100.2: Vortrag
Donnerstag, 19. März 2020, 10:45–11:00, REC C 213
Measuring the scattering phase shifts of single non-magnetic impurity atoms buried in Cu by STM — •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
Scattering in a solid due to impurity atoms and other crystal imperfections has been subject of research for decades because of its fundamental significance for our understanding of matter and its application in technology. Various experimental approaches have been used to access bulk scattering properties, especially the phase shift, which can be determined by transport properties or the de Haas-van Alphen effect. Here, we use a UHV-low temperature scanning tunneling microscope (STM) to measure the effective scattering phase shift of a single, non-magnetic impurity buried below a Cu(100) surface. We compare silver and germanium atoms by their LDOS surface signature which is created by standing electron waves in the crystal due to electron focusing. We reproduce the experimental topographies accurately with a simple tight-binding model that we use to determine the phase shift. The experimental values match for both species with calculations based on density functional theory. Furthermore, in energy-dependent data we find that the simple model of a Lorentzian scatterer has to be extended to characterize a non-magnetic atom on the local scale. This work was supported by DFG projects LO 1659/5-1 and WE 1889/8-1.