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arXiv 1406.3771cond-mat.mes-hallcond-mat.mtrl-scicond-mat.str-el
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电子振动对分子结热电效率的影响

Electron-vibration effects on the thermoelectric efficiency of molecular junctions

C. A. Perroni, D. Ninno, V. Cataudella

摘要:

在室温下的线性制度的非平衡绝热方法内的热电性能的分子结模型,适合于大分子,如富勒烯,进行了研究。一个自洽的计算实现电子和声子的热导表明,两者都增加与列入电子振动耦合。此外,我们表明,从Wiedemann-Franz定律的偏差逐渐减少时,增加电子和振动自由度之间的相互作用。因此,结热电效率由于电子-振动耦合而大大降低。即使如此,对于实际的参数值,热电优值仍然可以具有单位数量级的峰值。最后,在非共振电子制度,我们的结果进行了比较,这是准确的低分子电子密度的方法。我们给出的证据表明,在这种情况下,额外的量子效应,不包括在本工作的第一部分,不影响显着的结热电性能在任何温度制度。

英文摘要:

The thermoelectric properties of a molecular junction model, appropriate for large molecules such as fullerenes, are studied within a non-equilibrium adiabatic approach in the linear regime at room temperature. A self-consistent calculation is implemented for electron and phonon thermal conductance showing that both increase with the inclusion of the electron-vibration coupling. Moreover, we show that the deviations from the Wiedemann-Franz law are progressively reduced upon increasing the interaction between electronic and vibrational degrees of freedom. Consequently, the junction thermoelectric efficiency is substantially reduced by the electron-vibration coupling. Even so, for realistic parameters values, the thermoelectric figure of merit can still have peaks of the order of unity. Finally, in the off-resonant electronic regime, our results are compared with those of an approach which is exact for low molecular electron densities. We give evidence that in this case additional quantum effects, not included in the first part of this work, do not affect significantly the junction thermoelectric properties in any temperature regime.

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