Pulling and Stretching a Molecular Wire to Tune its Conductance.
A scanning tunnelling microscope is used to pull a polythiophene wire from a Au(111) surface while measuring the current traversing the junction. Abrupt current increases measured during the lifting procedure are associated with the detachment of molecular subunits, in apparent contradiction with the expected exponential decrease of the conductance with wire length. Ab initio simulations reproduce the experimental data and demonstrate that this unexpected behavior is due to release of mechanical stress in the wire, paving the way to mechanically gated single-molecule electronic devices.
†IPCMS de Strasbourg, UMR 7504 (CNRS - Université de Strasbourg), 67034 Strasbourg, France.
Gaël
G
Reecht
†IPCMS de Strasbourg, UMR 7504 (CNRS - Université de Strasbourg), 67034 Strasbourg, France.
Hervé
H
Bulou
†IPCMS de Strasbourg, UMR 7504 (CNRS - Université de Strasbourg), 67034 Strasbourg, France.
Fabrice
F
Scheurer
†IPCMS de Strasbourg, UMR 7504 (CNRS - Université de Strasbourg), 67034 Strasbourg, France.
Virginie
V
Speisser
‡Institut Parisien de Chimie Moléculaire, Chimie des Polymères, UMR 8232, (CNRS - Université Pierre et Marie Curie), 75252 Paris, France.
Fabrice
F
Mathevet
§Service de Physique de l'Etat Condensé, DSM/IRAMIS/SPEC, CNRS UMR 3680, CEA Saclay, 91191 Gif sur Yvette cedex, France.
César
C
González
§Service de Physique de l'Etat Condensé, DSM/IRAMIS/SPEC, CNRS UMR 3680, CEA Saclay, 91191 Gif sur Yvette cedex, France.
Yannick J
YJ
Dappe
†IPCMS de Strasbourg, UMR 7504 (CNRS - Université de Strasbourg), 67034 Strasbourg, France.
Guillaume
G
Schull
Molecular junction; density functionnal theory; polythiophene; scanning tunnelling microscopy