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Stretching-Induced Conductance Increase in a Spin-Crossover Molecule
Riccardo Frisenda1, Gero D Harzmann2, Jose A Celis Gil1
1Kavli Institute of Nanoscience, Delft University of Technology , 2600 GA Delft, The Netherlands.
Nano Letters
|April 19, 2016
Summary
We demonstrate mechanically controlled single-molecule switches using iron(II) complexes. Mechanical force alters the iron coordination sphere, switching its spin state and significantly changing electrical conductance.
Area of Science:
- Molecular Electronics
- Supramolecular Chemistry
- Spin Crossover Materials
Background:
- Single-molecule switches are crucial for nanoscale electronic devices.
- Iron(II) complexes with spin-crossover properties offer tunable electronic behavior.
- Mechanical control over molecular conformation can influence electronic transport.
Purpose of the Study:
- To investigate transport properties of mechanically triggered single-molecule switches.
- To explore the role of spin-crossover in Fe(II)-complexes for mechanical switching.
- To correlate mechanical manipulation with changes in electrical conductance.
Main Methods:
- Fabrication of molecular junctions using mechanically controlled break-junction (MCBJ) technique.
- Cryogenic temperature current-voltage (I-V) measurements.
- Theoretical calculations to model spin transitions and electron transmission.
Main Results:
- A significant fraction of junctions showed a 1-2 order of magnitude conductance increase with increasing electrode separation.
- Observed conductance changes support a switching mechanism based on spin-crossover behavior.
- Theoretical calculations confirm stretching-induced spin transition and higher transmission in the high-spin state.
Conclusions:
- Mechanically controlled distortion of Fe(II) coordination spheres can trigger spin-crossover.
- This spin-state modulation effectively switches molecular junction conductance.
- The study validates the use of spin-crossover molecules as mechanically actuated switches.
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