Conductance switching in a molecular device: the role of sidegroups and intermolecular interactio

TL;DR

This study uses first-principles calculations to explore how side groups influence electronic transport and conformational behavior in monolayers of functionalized Tour wires, revealing effects on conductance and molecular memory.

Contribution

It provides new insights into how side groups affect intermolecular interactions and electronic properties in molecular monolayers, especially regarding conformational changes and negative differential resistance.

Findings

Side groups do not significantly alter transmission resonances.

NO₂ groups induce conformational minima related to twisting.

Bias-induced twisting explains negative differential resistance.

Abstract

We report first-principles studies of electronic transport in monolayers of Tour wires functionalized with different side groups. An analysis of the scattering states and transmission eigenchannels suggests that the functionalization does not strongly affect the resonances responsible for current flow through the monolayer. However, functionalization has a significant effect on the interactions within the monolayer, so that monolayers with NO$_2$ side groups exhibit local minima associated with twisted conformations of the molecules. We use our results to interpret observations of negative differential resistance and molecular memory in monolayers of NO$_2$ functionalized molecules in terms of a twisting of the central ring induced by an applied bias potential.