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Large Converse Piezoelectric Effect Measured on a Single Molecule on a Metallic Surface

Publikace na Přírodovědecká fakulta |
2018

Tento text není v aktuálním jazyce dostupný. Zobrazuje se verze "en".Abstrakt

The converse piezoelectric effect is a phenomenon in which mechanical strain is generated in a material due to an applied electrical field. In this work, we demonstrate the Converse piezoelectric effect in single heptahelicene-derived molecules on the Ag(111) surface using atomic, force microscopy (AFM) and total energy density functional theory (DFT) calculations.

The force distance spectroscopy acquired over a wide range of bias voltages reveals a linear shift of the tip sample distance at which the contact between the molecule and tip apex is established. We demonstrate that this effect is caused by the bias-induced deformation of the spring-like scaffold of the helical polyaromatic molecules.

We attribute this effect to coupling of a soft vibrational mode of the molecular helix with a vertical electric dipole induced by molecule substrate charge transfer. In addition, we also performed the same spectroscopic measurements on a more rigid o-carborane dithiol molecule on the Ag(111) surface.

In this case, we identify a weaker linear electromechanical response, which underpins the importance of the helical scaffold on the observed piezoelectric response.