Atomic-scale engineering of electrodes for single-molecule contacts
Atomic-scale engineering of electrodes for single-molecule contacts
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DOI：
10.1038/nnano.2010.215
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发表时间：
2011-01-01
影响因子：
38.3
通讯作者：
Berndt, Richard
中科院分区：
文献类型：
--
作者：
Schull, Guillaume;Frederiksen, Thomas;Berndt, Richard
电荷通过导电材料的传输取决于材料传导电流的固有能力以及导体与将电流输送到材料和从材料输送电流的电极之间的接触处的电荷注入效率（1-3）。根据理论上的考虑（4），这一概念在单分子结的极限下仍然有效（5）。在实验中探索这一限制需要对结的几何形状进行原子尺度的控制。在这里，我们提出了一种方法，用于探测通过单个C（60）分子的电流，同时逐个改变电极中与分子接触的原子数。我们定量地表明，接触的几何形状有很强的影响电导。我们还发现了一个交叉从一个政权，其中电导是有限的电荷注入在接触的政权，其中电导是有限的散射在分子。因此，通常用于宏观和介观物理学的“好”和“坏”接触的概念也可以应用于分子尺度。
The transport of charge through a conducting material depends on the intrinsic ability of the material to conduct current and on the charge injection efficiency at the contacts between the conductor and the electrodes carrying current to and from the material(1-3). According to theoretical considerations(4), this concept remains valid down to the limit of single-molecule junctions(5). Exploring this limit in experiments requires atomic-scale control of the junction geometry. Here we present a method for probing the current through a single C(60) molecule while changing, one by one, the number of atoms in the electrode that are in contact with the molecule. We show quantitatively that the contact geometry has a strong influence on the conductance. We also find a crossover from a regime in which the conductance is limited by charge injection at the contact to a regime in which the conductance is limited by scattering at the molecule. Thus, the concepts of 'good' and 'bad' contacts, commonly used in macro- and mesoscopic physics, can also be applied at the molecular scale.