中文摘要：

采用基于密度泛函理论的非平衡格林函数方法，研究了以Au（111）面为电极、DNA的单个碱基（包括主链上的糖基和磷酸基）置于其间的两电极体系的电输运特性．在电极距离固定的情况下，通过改变碱基与电极的接触距离，分别计算了零偏压下DNA碱基处于不同耦合强度时的横向电导和传输谱．结果表明碱基的横向电输运性质受耦合强度的影响较大；除了鸟嘌呤G的氢键靠近电极时电导比腺嘌呤A小之外，碱基的电导排序符合G〉A〉C〉T．

英文摘要：

The electronic transport properties of a two-probe system, which consists of two Au （111 ） electrodes and the single DNA nudeotide base sandwiched between two Au （111） contacts, are investigated by density functional theory combined with non-equilibrium Green＇s function method. Fixing the gap between two electrodes and by changing the contact distance between the base and the electrode, the transverse conduetanee and transmission spectrum of the DNA bases under zero bias are calculated under different coupling strength. The results denote that the effects of coupling strength between the electrodes and the bases on the transverse electronic transport properties of DNA are very obvious. Except the conductance of guanine G is smaller than adenine A when hydrogen bonds of G is near the electrode, the order of conductance of the bases is G〉A〉C〉T.