Regensburg 2022 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 13: Quantum Dots, Quantum Wires, Point Contacts
TT 13.5: Talk
Tuesday, September 6, 2022, 10:30–10:45, H23
Evolution of single-level-model parameters in the mechanically controllable break junctions — •M. Lokamani1,2, F. Kilibarda2, F. Günther3, J. Kelling1, A. Strobel2, P. Zahn2, G. Juckeland1, K. Gothelf4, E. Scheer5, S. Gemming6, and A. Erbe2 — 1FWCC, HZDR, Dresden, Germany — 2FWIO, HZDR, Dresden, Germany — 3IFSC, São Carlos, Brazil — 4iNANO, Aarhus, Denmark — 5Department of Physics, Uni Konstanz, Germany — 6Institute of Physics, TU Chemnitz, Germany
The electrical properties of single molecules can be investigated using atomically sharp metallic electrodes in mechanically controllable break junctions (MCBJs). The current-voltage (IV) characteristics of single molecules in such junctions are influenced by the binding positions of the end groups on the tip-facets and tip-tip separation. In this talk, we present MCBJ experiments on N,N’-Bis(5-ethynylbenzenethiol-salicylidene)ethylenediamine (Salen). We discuss the evolution of the single level model (SLM) parameters namely, a) the energetic level є of the dominant conducting channel and b) the coupling Γ of the dominant conducting channel to the metallic electrodes. The SLM-parameters were evaluated for IV-curves recorded during opening measurements and fitted to the single level model. We propose a novel, high-throughput approach to model the evolution of the SLM-parameters and explain the recurring peak-like features in the experimentally measured evolution of Γ with increasing tip-tip separation, which we relate to the deformation of the molecule and the sliding of the anchor group above the electrode surface.