碳链输运对基团吸附的敏感性分析

基于局域原子轨道的密度泛函理论和非平衡格林函数方法，研究了碳链输运特性对分别吸附7种常见官能团NO₂, CN, CHO, Br, C₆H₅, C₅H₄N和NH₂时的敏感性. 计算表明，电流对C₆H₅和CHO的吸附最为敏感，其次是对CN和C₅H₄N的吸附，在某些偏压下电流有大幅度的下降，其值关键词：碳链输运特性密度泛函理论非平衡格林函数

Analysis on transport sensitivity for a carbon atomic wire attached with side groups

Based on the local atomic-orbital density functional theory plus the nonequilibrium Green’s function approach, we study the transport sensitivities of a carbon atomic wire attached, respectively with seven kinds of commonly seen side-groups NO₂, CN, CHO, Br, C₆H₅, C₅H₄N, NH₂. The calculated results show that the transport current is most sensitive to attached C₆H₅ and CHO groups, less sensitive to attached CN and C₅H₄N groups. Under certain bias values, the currents have a substantial decline and would reached to 1/2, or even 1/3 the magnitude as the unattached system C₆. But the transport of the carbon atomic wire is little influenced by the attached NO₂, NH₂, and Br. The intrinsic origins of side-group effects on the transport current in the wire are the suppression of the transmission eigen-channel, change of the Mulliken population, diminution of the delocalization of highest occupied molecular orbital or lowest unoccupied molecular orbital, and alteration of the resonant molecular orbital.