Transition from Strong to Weak Electronic Coupling in a Single-Molecule Junction

Transition from Strong to Weak Electronic Coupling in a Single-Molecule Junction

Frisenda, R. (TU Delft QN/van der Zant Lab; Kavli institute of nanoscience Delft)
van der Zant, H.S.J. (TU Delft QN/van der Zant Lab; Kavli institute of nanoscience Delft)

2016

We have investigated charge transport in single-molecule junctions using gold nanoelectrodes at room and cryogenic (10 K) temperatures. A statistical analysis of the low-bias conductance, measured during the stretching of the molecular junctions, shows that the most probable single-molecule conductance is insensitive to the temperature as expected for off-resonant coherent transport. Low-temperature current-voltage measurements show that these junction conformations have a smooth tunnelinglike shape. While separating the electrodes further we find that, in about one-fourth of the cases, the junction switches in an abrupt way to a configuration with I-V characteristics exhibiting a gap around zero bias and resonances at finite bias. The analysis of the I-V shape and of the conductance distance dependence suggests a stretching-induced transition from the strong to the weak electronic coupling regime. The transition involves a large renormalization of the injection barrier and of the electronic coupling between the molecule and the electrodes.

http://resolver.tudelft.nl/uuid:dd40191c-bb8c-4a35-8043-36f1c0d29d4f

https://doi.org/10.1103/PhysRevLett.117.126804

0031-9007

Physical Review Letters, 117 (12)

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journal article

© 2016 R. Frisenda, H.S.J. van der Zant