Regensburg 2010 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 35: TR: Nanoelectronics III: Molecular Electronics 1
TT 35.8: Talk
Thursday, March 25, 2010, 16:00–16:15, H21
Spin degrees of freedom in single-molecule junctions — •Stefan Wagner1, Stefan Ballmann1, Daniel Secker1, Frank Schramm2, Mario Ruben2, and Heiko B. Weber1 — 1Lehrstuhl für Angewandte Physik, Universität Erlangen-Nürnberg, Staudtstr. 7/A3, D-91058 Erlangen, Germany — 2Institut für Nanotechnologie, Forschungszentrum Karlsruhe, D-76021 Karlsruhe, Germany
We report on transport measurements on single molecules with spin degrees of freedom.
Fe2+-bis(pyrazolyl)pyridine is known as a spin transition compound, in which the Fe2+ atom carries either no spin or S = 2, depending on its local environment. We find qualitatively different zero bias anomalies at very low temperatures, in particular a Kondo feature, but also an unconventional dip-like feature in dI/dV. The anomalies and their behavior in magnetic fields are explained by singlet-triplet transitions and magnetic anisotropy.
In addition, a Bis(Co2+)bipyrimidine-wire is investigated, with two Co2+ ions. Here, we see two states in the low-bias anomaly, referring to a singlet and multiplet states of the ion pair.