Contact interference in molecular junctions

Abstract

We highlight a new manifestation of quantum interference in transport through single-molecule junctions, owing to different charge transport pathways from the molecule through the contacts into the three-dimensional electrode. Such contact interference can be identified with characteristic features of the current–voltage curve, as dramatic as closing an otherwise open transport channel. Based on analysis of the necessary conditions for observation of this phenomenon, we conclude that this effect should be detectable in relatively small molecules, where a molecular site shares coupling to two electrodes, and an electrode surface site shares coupling to different molecular sites. The importance of the surface-molecule connectivity scheme implies that commonly used reduced models which couple different molecular sites to effectively independent electrodes, fail to account for this effect and must be corrected in order to properly capture contact interference.

GRAPHICAL ABSTRACT

KEYWORDS:

• Molecular electronics
• single molecule junctions
• quantum transport
• quantum interference

Acknowledgments

This work is dedicated to Prof. Nimrod Moiseyev for his continuous scientific inspiration and friendship. A.D.L. acknowledges scholarship by the Technion Graduate School.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The research was supported by the Israel Science Foundation.