外加电压对分子器件电子输运特性的影响：非线性输运性质

根据第一性原理计算了由外电场引起的分子的几何结构和电子结构的变化，并利用弹性格林函数的方法计算了分子器件的电输运特性，从而研究了外电场对1,4-苯二硫酚分子电子输运特性的影响。计算结果表明，对于前线分子轨道，能级的移动和分子末端格点的展开系数在低电压范围内随外电压基本成线性变化。外电场对分子器件的伏安特性有很明显的影响，特别是对电导曲线的形状。考虑电场后的理论结果与实验结果符合得较好。

Influence of external voltage on electronic transport properties of molecular junctions: the nonlinear transport behaviour

The influence of external voltage on the charge transport properties of benzene-1,4-dithiolate molecular junction has been investigated. Variations of the geometric and electronic structures for the molecule caused by the applied voltage are calculated at ab initio level. Based on the numerical results, we find that the energy shift and expansion coefficients in the end-site of the molecule for the frontier molecular orbitals show nearly linear dependence on voltage in the interesting voltage interval. The charge transport properties of the molecular junction are then studied by employing the elastic scattering Green’s function method. It is shown that the voltage has an obvious effect on the I-V characteristic of the molecular junction, particularly the shape of the conductance curves. The I-V curves are consistent with the experimental measurement quite well.