TY - JOUR
T1 - Understanding the Role of Parallel Pathways via In-Situ Switching of Quantum Interference in Molecular Tunneling Junctions
AU - Soni, Saurabh
AU - Ye, Gang
AU - Zheng, Jueting
AU - Zhang, Yanxi
AU - Asyuda, Andika
AU - Zharnikov, Michael
AU - Hong, Wenjing
AU - Chiechi, Ryan C.
PY - 2020/8/17
Y1 - 2020/8/17
N2 - This study describes the modulation of tunneling probabilities in molecular junctions by switching one of two parallel intramolecular pathways. A linearly conjugated molecular wire provides a rigid framework that allows a second, cross-conjugated pathway to be effectively switched on and off by protonation, affecting the total conductance of the junction. This approach works because a traversing electron interacts with the entire quantum-mechanical circuit simultaneously; Kirchhoff's rules do not apply. We confirm this concept by comparing the conductances of a series of compounds with single or parallel pathways in large-area junctions using EGaIn contacts and single-molecule break junctions using gold contacts. We affect switching selectively in one of two parallel pathways by converting a cross-conjugated carbonyl carbon into a trivalent carbocation, which replaces destructive quantum interference with a symmetrical resonance, causing an increase in transmission in the bias window.
AB - This study describes the modulation of tunneling probabilities in molecular junctions by switching one of two parallel intramolecular pathways. A linearly conjugated molecular wire provides a rigid framework that allows a second, cross-conjugated pathway to be effectively switched on and off by protonation, affecting the total conductance of the junction. This approach works because a traversing electron interacts with the entire quantum-mechanical circuit simultaneously; Kirchhoff's rules do not apply. We confirm this concept by comparing the conductances of a series of compounds with single or parallel pathways in large-area junctions using EGaIn contacts and single-molecule break junctions using gold contacts. We affect switching selectively in one of two parallel pathways by converting a cross-conjugated carbonyl carbon into a trivalent carbocation, which replaces destructive quantum interference with a symmetrical resonance, causing an increase in transmission in the bias window.
KW - EGaIn
KW - molecular electronics
KW - quantum interference
KW - self-assembled monolayers
KW - STM-BJ
UR - http://dx.doi.org/10.1002/anie.202005047
U2 - 10.1002/anie.202005047
DO - 10.1002/anie.202005047
M3 - Article
SN - 1433-7851
VL - 59
SP - 14308
EP - 14312
JO - Angewandte Chemie (international edition)
JF - Angewandte Chemie (international edition)
IS - 34
ER -