单分子器件电子输运性质的理论研究

Theoretical Study on the Electron Transport Properties of Single Molecular Bridge

对当前单分子器件的理论和实验的研究进展作了简短评述,并简要介绍电子输运理论,最后给出一个基于非平衡态格林函数电子输运理论的全自洽方法,研究单个水分子在Au(111)电极之间的输运性质的计算实例.研究结果表明由于水分子与电极之间存在较强的杂化作用,水分子的分立能级间距大,在小偏压范围内,水分子的特征已经被淹没在杂化能级之中.体系的电势变化主要发生在水分子局域区间,其电子输运行为主要是一个单通道过程.

In this review the highlights of both experimental and theoretical studi es on single molecular device as well as the standard elastic electronic transport theory combining wi th Green's function technique are in tro-duced concisely.A theoretical stud y on transport properties of a H 2 O molecule bridged between two Au (111)surface is carried out by using full s elf-consistent first-principles m ethod and non-equilibrium Green's f unctions method.The results show that there i s a strong hybridization between H 2 O molecule and Au surface atoms of the electrodes.The molecular characte r of H 2 O molecule is largely conserved by states of Au atoms of electrodes at a small bias voltage.The potential distribution locates the local regio n around H 2 O molecule.The conductance of a single H 2 O molecule bridged between two Au ele ctrodes is mainly contributed by a single channel.