Large Conductance Variations in a Mechanosensitive Single-Molecule Junction

TL;DR

This paper demonstrates that mechanical deformation of a single-molecule junction can significantly modulate its conductance through quantum interference, enabling potential applications in sensitive room-temperature sensors.

Contribution

It introduces a method to mechanically tune molecular conductance by controlling quantum interference, revealing large conductance variations in a single-molecule junction.

Findings

Conductance can be tuned by up to an order of magnitude through mechanical manipulation.

Oscillations in conductance occur due to stick-slip motion of anchoring groups.

Mechanical control of quantum interference enables potential sensing applications.

Abstract

The appealing feature of molecular electronics is the possibility of exploiting functionality built within a single molecule. This functionality can be employed, for example, for sensing or switching purposes. Thus, ideally, the associated conductance changes should be sizable upon application of external stimuli. Here, we show that a molecular spring can be mechanically compressed or elongated to tune its conductance by up to an order of magnitude by controlling the quantum interference between electronic pathways. Oscillations in the conductance occur when the stress built up in the molecule is high enough to allow the anchoring groups to move along the surface in a stick-slip-like fashion. The mechanical control of quantum interference effects and the resulting large change in molecular conductance open the door for applications in, e.g., a minute mechanosensitive sensing device functional at room temperature.