First-principles study of phenyl ethylene oligomers as current-switch

TL;DR

This study employs first-principles calculations to analyze the current-switching behavior of phenyl ethylene oligomers, confirming experimental results and exploring the effects of molecular modifications on transport properties.

Contribution

It introduces a self-consistent first-principles approach to investigate molecular current-switches and examines the influence of molecular rotations and substitutions on switching behavior.

Findings

Numerical results agree with early experimental data.

Rotation of the middle ring affects the switching behavior.

Substituting hydrogen alters I-V asymmetry but maintains switching in both bias ranges.

Abstract

We use a self-consistent method to study the distinct current-switch of $2^{'}$-amino-4-ethynylphenyl-4'-ethynylphenyl-5'-nitro-1-benzenethiol, from the first-principles calculations. The numerical results are in accord with the early experiment [Reed et al., Sci. Am. \textbf{282}, 86 (2000)]. To further investigate the transport mechanism, we calculate the switching behavior of p-terphenyl with the rotations of the middle ring as well. We also study the effect of hydrogen atom substituting one ending sulfur atom on the transport and find that the asymmetry of I-V curves appears and the switch effect still lies in both the positive and negative bias range.