Understanding the Role of Parallel Pathways via In-Situ Switching of Quantum Interference in Molecular Tunneling Junctions

作     者：Soni S. Ye G. Zheng J. Zhang Y. Asyuda A. Zharnikov M. Hong W. Chiechi R.C. 

作者机构：Stratingh Institute for Chemistry University of Groningen Nijenborgh 4 Groningen 9747 AG Netherlands Zernike Institute for Advanced Materials Nijenborgh 4 Groningen 9747 AG Netherlands Center for Biomedical Optics and Photonics (CBOP) & College of Physics and Optoelectronic Engineering Key Laboratory of Optoelectronic Devices and Systems Shenzhen University Shenzhen 518060 China State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 China Microsystems Department of Mechanical Engineering and Institute for Complex Molecular Systems Eindhoven University of Technology Eindhoven 5600 MB Netherlands Applied Physical Chemistry Heidelberg University Im Neuenheimer Feld 253 Heidelberg D-69120 Germany 

出 版 物：《Angewandte Chemie》 

年 卷 期：2020年第132卷第34期

页      面：14414-14418页

学科分类：081704[工学-应用化学] 08[工学] 0817[工学-化学工程与技术] 

基　　金：China Scholarship Council  CSC China Scholarship Council  CSC: 201408440247 Helmholtz Zentrum München European Research Council  ERC 2017YFA0204902 European Research Council  ERC: 335473 National Natural Science Foundation of China  NSFC: 21673195 

主　　题：EGaIn molecular electronics quantum interference self-assembled monolayers STM-BJ 

摘      要：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. © 2020 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.