Berlin 2012 – scientific programme

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O: Fachverband Oberflächenphysik

O 79: Experimental methods

O 79.1: Talk

Thursday, March 29, 2012, 16:00–16:15, A 060

Scanning tunneling potentiometry on the Au/Ge(001) surface — •Christian A. Bobisch¹, Mark R. Kaspers¹, Alexander M. Bernhart¹, Mateusz Wojtaszek², Franciszek Krok², Marek Szymonski², and Rolf Möller¹ — ¹Faculty of Physics, Center for Nanointegration Duisburg-Essen, University of Duisburg-Essen, 47048 Duisburg, Germany — ²Department of Physics of Nanostructures and Nanotechnology, Jagiellonian University, 30-059 Krakow, Poland

Recently many studies focus on self organized Au atom wires on the Ge(001) surface. This surface offers the unique opportunity to study a Tomonoga-Luttinger liquid, i.e. a one dimensional electronic system [1,2]. In order to study electron transport through such a surface, the coupling of the metallic leads to the surface is a crucial parameter. We use a multiprobe scanning tunneling microscope (STM) to analyze the lateral variation of the electrochemical potential caused by a current parallel to the surface induced by two tips. In the scheme of scanning tunneling potentiometry a third STM tip measures the topography and the electrochemical potential µ_ec of the surface simultaneously [3]. The excess amount of Au deposited onto the Ge(001) surface condenses into crystalline islands. However, our potentiometry data reveal a discontinuity of µ_ec at the edges of these islands. This indicates that the islands do not couple to the electronic system of the Au reconstructed Ge(001) surface.

[1] Phys. Rev. Lett. 101, 236802 (2008). [2] Nat. Phys. 7, 776, (2011). [3] Nano Lett. 9, 1588 (2009).