Dresden 2011 – scientific programme
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O: Fachverband Oberflächenphysik
O 36: Poster Session II (Metals; Nanostructures at surfaces; Surface or interface magnetism; Spin-Orbit Interaction at Surfaces; Electron and spin dynamics; Surface dynamics; Methods; Theory and computation of electronic structure)
O 36.60: Poster
Tuesday, March 15, 2011, 18:30–22:00, P4
Controlled coupling of interface quantum well states — •Willi Auwärter1, Knud Seufert1, David Ecija1, Niveditha Samudrala1, Saranyan Vijayaraghavan1, Sushobhan Joshi1, F. Javier Garcia de Abajo2, and Johannes V. Barth1 — 1Physik Department E20, Technische Universität München, 85748 Garching, Germany — 2Instituto de Optica, CSIC, 28006 Madrid, Spain
The confinement of surface state electrons in artificial nanostructures permits exploring and visualizing fundamental aspects of quantum mechanics. Here, we introduce a new approach to engineer quantum wells by combining a scanning tunneling microscope manipulation technique with recipes for molecular self-assembly on surface-state-supporting surfaces. Following this procedure, we can not only fabricate resonators of varying size, but also build specific arrangements of quantum wells, such as dimers or one-dimensional chains. The electronic structure of such coupled systems, representing artificial molecules, is studied by local scanning tunneling spectroscopy. Hereby, the scattering characteristics of the potential walls enclosing the wells are determined by the molecules employed as barriers. In particular, we compare quantum well states in free-base and metalated porphyrin arrays on Ag(111). The experimental data on the electron confinement and the coupling of quantum wells are corroborated by boundary element method calculations. These simulations might also be used to design structures with specific electronic properties.