Berlin 2018 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 12: Focus: Molecularly Functionalized Low-Dimensional Systems II - organized by Antonio Setaro, Carola Meyer, Aravind Vijayaraghvan and Matteo Mannini

CPP 12.1: Topical Talk

Montag, 12. März 2018, 15:00–15:30, C 130

Magnetoresistance in Single-Radical Molecular Junctions — •Elke Scheer — Department of Physics, University of Konstanz, 78457 Konstanz

We study the charge transport properties of single radical molecule junctions formed by a break junction technique at 4.2 K in magnetic field B. In this study, stable and neutral radical molecules based on an oligo(p-phenylene ethynylene) (OPE) backbone with a radical attAched to its side (TEMPO-OPE) are contacted with freestanding and tunable gold (Au) electrodes. In perpendicular field we observe large positive magnetoresistance (MR) up to 287 % at 4T [1]. The average MR amplitude is one order of magnitude larger than that of the analogous non-radical OPE molecule. In parallel field a step-like negative MR occurs with the same amplitude on field scales of 2-3 T. The analysis of the MR, of current-voltage characteristics and of inelastic electron tunneling spectra reveal an effective reduction of the electronic coupling between the current-carrying frontier orbital and the metal electrodes with increasing B. Our findings thus provide a new physical approach for tuning the charge transport through radical molecules. [1] R. Hayakawa et al. Nano Lett. 16, 4960 (2016).