Dresden 2014 – scientific programme

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DS: Fachverband Dünne Schichten

DS 45: Poster IV: One-Dimensional Metals: Reality or Fiction

DS 45.1: Poster

Thursday, April 3, 2014, 16:00–19:00, P1

Structural investigations of Au quantum wires on Ge(100) — •Heiko Teiken, Timo Lichtenstein, Christoph Tegenkamp, and Herbert Pfnür — Leibniz Universität Hannover, Institut für Festkörperphysik, AbteilungATMOS, 30167 Hannover

Ge(100) is known as a substrate for self-organized growth of one dimensional quantum wires by adsorption of Au. As shown recently (C. Blumenstein et.al. Nature 7, 776) the signatures of a Luttinger liquid behavior depends crucially on the quality of the ensemble and, consequently, on the quality of the Ge(100) sample prior to adsorption. Furthermore, there is a debate regarding details of the atomic structure of the atomic wires induced upon Au adsorption. In this study we have measured systematically roughness parameters on variously prepared surfaces by means of spot profile analysis of low energy electron diffraction patterns (SPA-LEED). From G(S)- and H(S)-analyses Ge- monoatomic step heights of 1.42Å with average terrace lengths around 20 nm are found. Ex-situ chemically treated Ge-samples followed by in-situ thermal annealing reveal slightly lower rms-values (1.3 Å) as samples which have undergone multiple in-situ sputter/annealing cycles. The G(S)-curves reveal additional structurs after growth of the Au-wires corresponding to step heights of 1.8 Å  which we suggest to be due to interference between gold covered islands and clean terraces. The overall roughness of the Ge-template does not increase due to growth of the Au-induced wires. Details of the G(S)-curves will be discussed in terms of different structural models (Au-dimer chains vs. Au-induced Ge-facet structures) currently proposed in literature.