Seth Charu, Kaliginedi Veerabhadrarao, Suravarapu Sankarrao, Reber David, Hong Wenjing, Wandlowski Thomas, Lafolet Frédéric, Broekmann Peter, Royal Guy, Venkatramani Ravindra
Department of Chemical Sciences , Tata Institute of Fundamental Research , Homi Bhabha Road, Colaba , Mumbai 400 005 , India . Email:
Department of Chemistry and Biochemistry , University of Bern , Freiestrasse 3, CH-3012 , Bern , Switzerland . Email:
Chem Sci. 2017 Feb 1;8(2):1576-1591. doi: 10.1039/c6sc03204d. Epub 2016 Nov 3.
Controlling charge flow in single molecule circuits with multiple electrical contacts and conductance pathways is a much sought after goal in molecular electronics. In this joint experimental and theoretical study, we advance the possibility of creating single molecule breadboard circuits through an analysis of the conductance of a bis-terpyridine based molecule (). The molecule can adopt multiple conformations through relative rotations of 7 aromatic rings and can attach to electrodes in 61 possible single and multi-terminal configurations through 6 pyridyl groups. Despite this complexity, we show that it is possible to extract well defined conductance features for the breadboard and assign them rigorously to the underlying constituent circuits. Mechanically controllable break-junction (MCBJ) experiments on the molecular breadboard show an unprecedented 4 conductance states spanning a range 10 to 10 . Quantitative theoretical examination of the conductance of reveals that combinations of 5 types of single terminal 2-5 ring subcircuits are accessed as a function of electrode separation to produce the distinct conductance steps observed in the MCBJ experiments. We estimate the absolute conductance for each single terminal subcircuit and its percentage contribution to the 4 experimentally observed conductance states. We also provide a detailed analysis of the role of quantum interference and thermal fluctuations in modulating conductance within the subcircuits of the molecular breadboard. Finally, we discuss the possible development of molecular circuit theory and experimental advances necessary for mapping conductance through complex single molecular breadboard circuits in terms of their constituent subcircuits.
在分子电子学中，通过多个电接触和电导路径来控制单分子电路中的电荷流动是一个备受追捧的目标。在这项联合实验与理论研究中，我们通过对一种基于双三联吡啶的分子（）的电导分析，推进了创建单分子试验电路板电路的可能性。该分子可通过7个芳香环的相对旋转采取多种构象，并可通过6个吡啶基以61种可能的单端和多端配置连接到电极上。尽管存在这种复杂性，但我们表明，有可能为该试验电路板提取明确的电导特征，并将它们严格地分配给潜在的组成电路。对该分子试验电路板进行的机械可控断裂结（MCBJ）实验显示出前所未有的4种电导状态，范围跨越10 至10 。对该分子电导的定量理论研究表明，5种类型的单端2 - 5环子电路的组合会随着电极间距的变化而被访问，从而产生在MCBJ实验中观察到的不同电导台阶。我们估计了每个单端子电路的绝对电导及其对4种实验观察到的电导状态的百分比贡献。我们还详细分析了量子干涉和热涨落在调节该分子试验电路板子电路内电导方面的作用。最后，我们讨论了分子电路理论的可能发展以及根据其组成子电路绘制复杂单分子试验电路板电路电导所需的实验进展。
