Regensburg 2016 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 47: Electronic Structure of Surfaces: Spectroscopy, Surface States

O 47.3: Poster

Dienstag, 8. März 2016, 18:15–20:30, Poster E

Force and Kelvin Probe Measurements on Confined Electronic States inside Quantum Resonators — •Fabian Queck, Florian Albrecht, and Jascha Repp — Institute of Experimental and Applied Physics, University of Regensburg, 93053 Regensburg, Germany

On close-packed surfaces of noble metals such as Cu(111) surface state electrons form a nearly free electron gas in two dimensions. The electrons are scattered from step-edges, point defects and adsorbates giving rise to standing wave patterns, which can be engineered by so-called quantum corrals (1). The standing wave patterns give rise to long range interactions between adsorbates (2) and should therefore be associated with measurable forces between scatterers.

At last year*s DPG meeting we presented preliminary results to directly measure these forces with atomic force microscopy and possible changes of the local contact potential difference arising from the modulation of the surface local density of states associated with the standing wave patterns. Here, we will present much more detailed atomic force microscopy and Kelvin probe spectroscopy data on this topic as well as electron density simulations that confirm our results.

(1) M. F. Crommie, C. P. Lutz, and D. M. Eigler. Confinement of Electrons to Quantum Corrals on a Metal Surface. Science, 262(5131):218*220, 1993.

(2) J. Repp. Rastertunnelmikroskopie und -spektroskopie an Adsorbaten auf Metall und Isolatoroberflaechen. PhD thesis, Freie Universitaet Berlin, 2002.