电极距离对分子器件电输运特性的影响

Effect of the distance between electrodes on the electronic transport properties of single molecular devices

以 4 ,4′_二巯基联苯分子为研究对象 ,利用从头计算方法和弹性散射格林函数理论 ,研究了两个电极之间的距离对分子几何结构和电子结构以及该分子结电输运性质的影响 .计算结果表明 ,电极距离的不同会改变分子的几何结构和电子结构 ,从而影响分子体系的电输运特性 .扩展分子的平衡状态不是电子输运的最佳状态 ,适当调整两个电极之间距离可以改善分子的电输运特性 .

Basing on ab initio methods and the elastic scattering Green function theory, we have investigated electronic transport properties of metal-molecule-metal junctions by taking the 4-4'-dimercaptodibenzene molecule as an example. The molecular geometric structures, electronic structures, and current-voltage characteristics have been studied for varying the distance between the two electrodes. Numerical results show that the changes of the distance between electrodes give various influence on the extended molecule's geometric and electronic structures, which brings effects on the electronic transport properties of the molecular systems. The equilibrium state of the extended molecule is not the best situation for electronic transportation. The characteristics of electronic transportation can thus be improved by adjusting the distance between the two electrodes.