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arXiv 1612.07643cond-mat.mes-hall
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无序分子纳米线的非平衡输运

Non-equilibrium transport through a disordered molecular nanowire

P. Thiessen, E. Diaz, R. A. Roemer, F. Dominguez-Adame

摘要:

研究了无序分子纳米线的非平衡输运性质。纳米线被认为是由分子自组装而成的准一维有机晶体。一个轨道和一个单一的随机能量分配给每个分子,而分子间的耦合不波动。因此,电子状态预计将空间本地化。我们考虑了强局域化的情况,即局域化长度小于分子线的长度。电子振动子相互作用,发生在每个单一的分子,也被考虑在内。我们调查之间的相互作用的无序和电子振动子相互作用响应于施加的电偏压或温度梯度。为此,我们计算的电流和热流时,纳米线连接到引线,使用Keldysh非平衡格林函数形式主义。在中等温度下,无序散射主导电荷和热输运。我们发现电子-振子相互作用增强了无序对输运性质的影响,这是由于隧穿的指数抑制。

英文摘要:

We investigate the non-equilibrium transport properties of a disordered molecular nanowire. The nanowire is regarded as a quasi-one-dimensional organic crystal composed of self-assembled molecules. One orbital and a single random energy are assigned to each molecule while the intermolecular coupling does not fluctuate. Consequently, electronic states are expected to be spatially localized. We consider the regime of strong localization, namely, the localization length is smaller than the length of the molecular wire. Electron-vibron interaction, taking place in each single molecule, is also taken into account. We investigate the interplay between disorder and electron-vibron interaction in response to either an applied electric bias or a temperature gradient. To this end, we calculate the electric and heat currents when the nanowire is connected to leads, using the Keldysh non-equilibrium Green's function formalism. At intermediate temperature, scattering by disorder dominates both charge and heat transport. We find that the electron-vibron interaction enhances the effect of the disorder on the transport properties due to the exponential suppression of tunneling.

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