A single atom change turns insulating saturated wires into molecular conductors

Xiaoping Chen, Bernhard Kretz, Francis Adoah, Cameron Nickle, Xiao Chi, Xiaojiang Yu, Enrique Barco, Damien Thompson, David A. Egger () and Christian A. Nijhuis ()
Additional contact information
Xiaoping Chen: National University of Singapore
Bernhard Kretz: Technical University of Munich
Francis Adoah: University of Central Florida
Cameron Nickle: University of Central Florida
Xiao Chi: National University of Singapore
Xiaojiang Yu: National University of Singapore
Enrique Barco: University of Central Florida
Damien Thompson: University of Limerick
David A. Egger: Technical University of Munich
Christian A. Nijhuis: National University of Singapore

Nature Communications, 2021, vol. 12, issue 1, 1-11

Abstract: Abstract We present an efficient strategy to modulate tunnelling in molecular junctions by changing the tunnelling decay coefficient, β, by terminal-atom substitution which avoids altering the molecular backbone. By varying X = H, F, Cl, Br, I in junctions with S(CH2)(10-18)X, current densities (J) increase >4 orders of magnitude, creating molecular conductors via reduction of β from 0.75 to 0.25 Å−1. Impedance measurements show tripled dielectric constants (εr) with X = I, reduced HOMO-LUMO gaps and tunnelling-barrier heights, and 5-times reduced contact resistance. These effects alone cannot explain the large change in β. Density-functional theory shows highly localized, X-dependent potential drops at the S(CH2)nX//electrode interface that modifies the tunnelling barrier shape. Commonly-used tunnelling models neglect localized potential drops and changes in εr. Here, we demonstrate experimentally that $$\beta \propto 1/\sqrt{{\varepsilon }_{r}}$$ β ∝ 1 / ε r , suggesting highly-polarizable terminal-atoms act as charge traps and highlighting the need for new charge transport models that account for dielectric effects in molecular tunnelling junctions.

Date: 2021
References: Add references at CitEc
Citations: View citations in EconPapers (1)

Downloads: (external link)
https://www.nature.com/articles/s41467-021-23528-8 Abstract (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:nat:natcom:v:12:y:2021:i:1:d:10.1038_s41467-021-23528-8

Ordering information: This journal article can be ordered from
https://www.nature.com/ncomms/

DOI: 10.1038/s41467-021-23528-8

Access Statistics for this article

Nature Communications is currently edited by Nathalie Le Bot, Enda Bergin and Fiona Gillespie

More articles in Nature Communications from Nature
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().