Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 25: Metal substrates: Adsorption of organic / bio molecules III

O 25.1: Vortrag

Dienstag, 23. März 2010, 10:30–10:45, H36

Tuning molecule-mediated spin coupling in bottom-up fabricated vanadium-TCNE nanostructures — •Daniel Wegner^1,2, Ryan Yamachika², Xiaowei Zhang², Yayu Wang², Tunna Baruah³, Mark R. Pederson⁴, Bart M. Bartlett², and Jeffrey R. Long² — ¹Physikalisches Intsitut & CeNTech, WWU Münster, Germany — ²University of California, Berkeley, and Lawrence Berkeley National Laboratory, Berkeley, CA, USA — ³University of Texas, El Paso, TX, USA — ⁴Naval Research Laboratory, Washington, DC, USA

We have fabricated hybrid organic/inorganic magnetic molecules based on vanadium atoms and tetracyanoethylene (TCNE) ligands in an atom-by-atom fashion using a cryogenic scanning tunneling microscope. By means of local tunneling spectroscopy we observe spin-polarized molecular orbitals as well as a structure-dependent Kondo resonance. For complexes having two V atoms, the Kondo behavior can be switched on and off by a minute structural change that leaves the spin-containing orbital essentially unchanged. This can be explained by a tunable, structure-dependent change in the vanadium spin-spin coupling strength through the TCNE molecule, as confirmed by density functional calculations. The present findings offer a new route for designing molecular spin nanostructures with atomic-scale precision.