Charge transport in strongly coupled molecular junctions: “in-phase” and “out-of-phase” contribution to electron tunneling
Charge transport in strongly coupled molecular junctions: “in-phase” and “out-of-phase” contribution to electron tunneling
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强耦合分子结中的电荷传输：对电子隧道的“同相”和“异相”贡献
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
R. Pati
中科院分区：
文献类型：
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作者：
P. Pal;R. Pati
我们报告的第一性原理研究的非平衡电荷输运的演变，在一个两端分子尺度的设备与增加的长度的分子导线建成了立方烷低聚物。特别是，对于三种不同长度的导线，我们期待的“同相”和“异相”的总电子电流的分量的外部偏置的影响下的相对贡献。在低偏压状态下，对总电流的“异相”贡献最小，并且电子的“同相”弹性隧穿负责净电子电流。这是真的，与分子间隔物的长度无关。在此范围内，电流-电压特性遵循欧姆定律，并且导线的电导随着长度的增加呈指数下降，这与实验结果一致。然而，在一定的“偏移”电压之后，电流随着偏置和“异相”隧穿非线性地增加。
We report a first-principles study on the evolution of nonequilibrium charge transport in a two-terminal molecular-scale device with the increase in the length of the molecular wire built out of cubane oligomers. In particular, for wires of three different lengths, we look into the relative contribution of the “in-phase” and the “out-of-phase” components of the total electronic current under the influence of an external bias. In the low-bias regime, the “out-of-phase” contribution to the total current is minimal and the “in-phase” elastic tunneling of the electrons is responsible for the net electronic current. This is true, irrespective of the length of the molecular spacer. In this regime, the current–voltage characteristics follow Ohm’s law and the conductance of the wires is found to decrease exponentially with the increase in length, which is in agreement with experimental results. However, after a certain “offset” voltage, the current increases nonlinearly with bias and the “out-of-phase” tunneling ...