Theory of electron transmission through atom bridges

The transmission eigenchannels of Al and Na atom bridges formed between jellium electrodes are investigated by a first-principles calculation. A transparent view on electronic transport in atom-size structures is provided by the decomposition of electronic states into eigenchannels. In particular we show how LDOS and current density resolved into eigenchannels reflect the spatial nature of atomic orbitals of the atoms composing the nanostructures. On the other hand, the eigenchannel DOS has already for the straight three-ill-atom bridge a 1D band character. From this we conclude that the transport through the single Al atom in this case mainly has a ID character (channel) in contrast to a OD resonant tunneling (dot) character. The effect of the bending of the bridge shape is significant for the Al bridges, but not for the Na bridges.