title: Stretching-Induced Conductance Increase in a Spin-Crossover Molecule.
abstract: We investigate transport through mechanically triggered single-molecule switches that are based on the coordination sphere-dependent spin state of Fe(II)-species. In these molecules, in certain junction configurations the relative arrangement of two terpyridine ligands within homoleptic Fe(II)-complexes can be mechanically controlled. Mechanical pulling may thus distort the Fe(II) 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 Fe(II)-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 Fe(II)-complex and a larger transmission for the high-spin configuration.
authors.affiliation: Kavli Institute of Nanoscience, Delft University of Technology , 2600 GA Delft, The Netherlands.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Frisenda
authors.affiliation: University of Base l, 4056 Basel, Switzerland.
authors.forename: Gero D
authors.initials: GD
authors.lastname: Harzmann
authors.affiliation: Kavli Institute of Nanoscience, Delft University of Technology , 2600 GA Delft, The Netherlands.
authors.forename: Jose A
authors.initials: JA
authors.lastname: Celis Gil
authors.affiliation: Kavli Institute of Nanoscience, Delft University of Technology , 2600 GA Delft, The Netherlands.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Thijssen
authors.affiliation: University of Base l, 4056 Basel, Switzerland.|Karlsruhe Institute of Technology (KIT) , P.O. Box 3640, 76021 Karlsruhe, Germany.|Lehn Institute of Functional Materials (LIFM), Sun Yat-Sen University (SYSU) , Gunagzhou, China.
authors.forename: Marcel
authors.initials: M
authors.lastname: Mayor
authors.affiliation: Kavli Institute of Nanoscience, Delft University of Technology , 2600 GA Delft, The Netherlands.
authors.forename: Herre S J
authors.initials: HS
authors.lastname: van der Zant
keywords: Spin-crossover switch; density functional theory; molecular spintronics; nanoscale transport