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

Abstract

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.