单硫醇分子结的几何结构和电输运性质:压力效应与末端基团效应

利用杂化密度泛函理论,研究了以甲基、醇基、羧基为末端基团的烷烃硫醇分子与金电极形成分子结的过程,得到了分子结的几何结构与外加压力的关系. 并在此基础上,利用弹性散射格林函数方法研究了烷烃硫醇分子的电输运性质. 研究结果表明,对于C₁₁S分子来说,当两电极距离大于2.1 nm时,该分子结断裂;对于C₁₁SOH和C₁₀SCOOH来说,相应的分子结断裂的电极距离基本相同(2.15 nm). 在相同的外加压力(4.0 nN)下,C_{11关键词： 压力 末端基团 烷烃硫醇分子 电输运性质}

Geometric structure and electronic transport property of single alkanemonothiol molecule junction: external force effect and terminal group effect

The hybrid density functional theory is used to study formation of the junction of alkanemonothiol molecules with different terminal groups. The relationship between geometric structures of the molecular junction and the external force is obtained. On the basis of the relationship, the electronic transport properties of the molecular junctions under different external forces are investigated using the elastic-scattering Green’s function method. The results show that the C₁₁S molecular junction is broken when the distance of the two electrodes is larger than 2.1 nm. While for C₁₁SOH and C₁₀SCOOH molecular junctions, their critical distances are similarly 2.15 nm. Taking the same external force, we find that the C₁₁S molecule has the largest conducting ability, and the C₁₀SCOOH molecule has the smallest conducting ability. Furthermore, the conductance of the three molecular junctions is monotonically enhanced with the increase of the external force. The numerical results are consistent with the experimental findings qualitatively.