Signatures of Quantum Interference Effects on Charge Transport Through a Single Benzene Ring
Signatures of Quantum Interference Effects on Charge Transport Through a Single Benzene Ring
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DOI：
10.1002/anie.201207667
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发表时间：
2013-01-01
影响因子：
16.6
通讯作者：
van der Zant, Herre S. J.
中科院分区：
文献类型：
--
作者：
Arroyo, Carlos R.;Tarkuc, Simge;van der Zant, Herre S. J.
直到最近，单分子传导实验大多被描述为非共振隧穿过程，其中分子作为隧穿屏障。[1-3]在这一描述中，能量势垒的宽度和高度以及分子与电极之间的电子耦合是表征电荷输运效率的主要参数。电子通过分子的转移依赖于电导路径的长度，这在许多实验中确实被观察到。[1,3 - 7]然而，这样一个简单的隧道图忽略了量子干涉效应，量子干涉效应可以在分子尺度上强烈影响传输。[8,9]因此，这些效应在理论上和实验上都引起了越来越多的科学兴趣。[16-20]单苯环是电荷输运中量子干涉效应最简单的系统之一理论上已经证明，在准构型中连接在两个电极之间的苯环的电导应该比元构型的电导高几个数量级。[13,21]这可以从苯环上沿不同途径的运输来理解。这些路径可以是空间路径，也可以是轨道路径。沿这些不同途径的输运组分的干扰可导致建设性或破坏性干扰。[10,11,13,22]
Until recently, single-molecule conduction experiments have mostly been described in terms of a nonresonant tunneling process where the molecule acts as a tunneling barrier.[1–3] In this description, the width and height of the energy barrier, and the electronic coupling between the molecule and the electrodes are the main parameters that characterize the efficiency of charge transport. Electron transfer through a molecule then depends exponentially on the length of the conductance pathway and this has indeed been observed in many experiments.[1, 3–7] However, such a simple tunneling picture disregards quantum interference effects that can strongly influence transport at the molecular scale.[8, 9] Therefore, these effects are a subject of growing scientific interest, both theoretically [10–15] and experimentally.[16–20] One of the simplest systems where quantum interference effects in charge transport are expected is a single benzene ring.[8] It has been shown theoretically that a benzene ring connected between two electrodes in a para-configuration should have a conductance that is several orders of magnitude higher than that of a meta-configuration.[13, 21] This can be understood in terms of transport along different pathways through the benzene ring. These pathways can be either spatial or orbital pathways. Interference of transport components along these different pathways can lead to constructive or destructive interference.[10, 11, 13, 22]