中文摘要：

基于第一性原理和弹性散射格林函数方法，从理论上研究了门电场对一系列有机单分子结的电输运性质的影响．结果显示，含有氧化还原中心并且在门电场方向具有较大电偶极矩的分子结能够对门电场有显著响应．2，5－二甲基噻吩二硫醇的伏安特性显示了类似N－沟道金属氧化物半导体管性质．这一独特的伏安特性可以从能级、耦合能以及原子电荷随门电场的演化来理解．

英文摘要：

Based on the first-principles computational method and elastic scattering Green＇s function theory, we have investigated the effect of gate electric field on electronic transport properties of a series of single organic molecular junctions theoretically. The numerical results show that the molecular junctions that have redox centers and relatively large dipole moments parallel gate direction can respond to the gate electric field remarkably. The current-voltage properties of 2,5-dimethyl-thiophene-dithiol present N-channel-metal-oxide-semiconductorlike characteristics. Its distinct current-voltage properties can be understood from the evo- lution of eigenvalues, coupling energies, and atomic charges with gate electric field.