Density-functional calculations and eigenchannel analyses for electron transport in Al and Si atomic wires

We perform first-principles calculations of the conductance of Al and Si atomic wires between jellium electrodes using the wave-function matching method combined with the density-functional theory. The calculated conductances for single-line and double-line atomic wires exhibit rich variation depending on the detailed atomic structure and the chemical difference between the constituent elements. The origin of the similarity and dissimilarity between Al and Si atomic wires is unequivocally clarified by our eigenchannel analyses of the wave functions and transmission probabilities obtained and by the calculated energy bands of the corresponding infinite-length atomic wires. We also find that the conductance of single-line Al wires increases upon stretching of the wires. This is due to peculiar features of the electron states of atomic wires consisting of group III or group IV atoms. The result is consistent with the observed conductance of Al wires.