Dresden 2017 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 20: Bio- and Molecular Magnetism

MA 20.3: Vortrag

Dienstag, 21. März 2017, 10:00–10:15, HSZ 301

Switching of a spin-crossover molecule on a surface — •Torben Jasper-Tönnies¹, Sujoy Karan¹, Hanne Jacob², Felix Tuczek², and Richard Berndt¹ — ¹Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel — ²Institut für Anorganische Chemie, Christian-Albrechts-Universität zu Kiel, 24098 Kiel

Spin-crossover (SCO) complexes contain a transition metal ion that can be switched between a low-spin and a high-spin state by external stimuli. An adsorbed SCO complex couples to the substrate and consequently may change its spin-switching property. Using low temperature scanning tunneling microscopy we investigated the SCO-compound [Fe(pap)₂]⁺ClO₄⁻ (pap= N-2-pyridylmethylidene-2-hydroxyphenylaminato) on substrates with supposedly different couplings to the molecule, namely Au(111), Cu(001) and Cu2N/Cu(001). Although we made various attempts, we found no indication of any STM tip induced modifications of Fe(pap)₂ on Au and Cu. By contrast, single Fe(pap)₂ on Cu₂N can be reproducibly and reversibly switched. We observed three states that exhibit different shapes in images and different spectroscopic features. We discuss the data in terms of conformational changes as well as spin-state modifications. Financial support by the SFB 677 is gratefully acknowledged.