Molecular Electronics: Effect of external electric field

TL;DR

This paper investigates how external electric fields influence nanoscale molecular systems, emphasizing the importance of bias potential profiles, electron interactions, and structural features in transport phenomena like negative differential resistance.

Contribution

It introduces the significance of bias potential profiles and explores NDR effects in insulators and quantum dots with electron-electron interactions, advancing understanding of molecular electronics.

Findings

Bias potential profile critically affects transport properties.

Structural features like sublattices induce NDR.

Electron-electron interactions can tune NDR behavior.

Abstract

The effect of electric field, applied on systems in the nanoscale regime has attracted a lot of research in recent times. We highlight some of the recent results in the field of single molecule electronics and then move on to focus on some of our own results in this area. We have first shown how important it is to obtain the spatial profile of the external bias potential across the system, and how this would change in the presence of electron-electron interactions. We have also studied different kinds of insulators in the presence of the spatially varying external bias, and have explicitly shown that a two sublattice structure, caused either by a lattice distortion, or by the presence of substituents with strong dipolar nature, can result in negative differential resistance (NDR) in the transport characteristics. We also find this to be true in case of correlated insulators. Additionally, we have shown clear NDR behavior in a correlated double quantum dot by tuning the electron-electron interaction strength in the system.