Pulling and Stretching a Molecular Wire to Tune its Conductance

Gaël Reecht (1) , Hervé Bulou (1) , Fabrice Scheurer (1) , Virginie Speisser (1) , Fabrice Mathevet (2) , César González (3) , Yannick J. Dappe (3) , Guillaume Schull (1)

1 IPCMS - Institut de Physique et Chimie des Matériaux de Strasbourg
2 IPCM - Institut Parisien de Chimie Moléculaire
3 SPEC - UMR3680 - Service de physique de l'état condensé

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.

Domains: Physics [physics]

Gaël Reecht, Hervé Bulou, Fabrice Scheurer, Virginie Speisser, Fabrice Mathevet, et al.. Pulling and Stretching a Molecular Wire to Tune its Conductance. Journal of Physical Chemistry Letters, 2015, 6 (15), pp.2987-2992. ⟨10.1021/acs.jpclett.5b01283⟩. ⟨cea-01366452⟩