Stretching-Induced Conductance Increase in a Spin-Crossover Molecule (Nano Letters cover article by Delft/QN PIs Herre van der Zant and Jos Thijssen and colleagues)



We investigate transport through mechanically triggered single-molecule switches that are based on the coordination sphere-dependent spin state of FeII-species. In these molecules, in certain junction configurations the relative arrangement of two terpyridine ligands within homoleptic FeII-complexes can be mechanically controlled. Mechanical pulling may thus distort the FeII coordination sphere and eventually modify their spin state. Using the movable nanoelectrodes in a mechanically controlled break-junction at low temperature, current–voltage measurements at cryogenic temperatures support the hypothesized switching mechanism based on the spin-crossover behavior. A large fraction of molecular junctions formed with the spin-crossover-active FeII-complex displays a conductance increase for increasing electrode separation and this increase can reach 1–2 orders of magnitude. Theoretical calculations predict a stretching-induced spin transition in the FeII-complex and a larger transmission for the high-spin configuration.

Riccardo Frisenda, Gero D. Harzmann, Jose A. Celis Gil, Joseph M. Thijssen, Marcel Mayor, and Herre S. J. van der Zant: 'Stretching-Induced Conductance Increase in a Spin-Crossover Molecule', Nano Lett., 2016, 16 (8), pp 4733–4737 DOI: 10.1021/acs.nanolett.5b04899

For the full article, click here.