Charge transport through small silicon clusters

With a recently developed ab initio nonequilibrium Green's-function formalism, we have investigated the transport behavior of small Si_n, n = 1 - 10, 13, and 20 nanoclusters between atomistic Al and Au leads. All of the clusters display metallic I-V characteristics, with typical conductances ranging between two and three (units of G_o= 2e²/h). The transport properties of these cluster junctions may be understood in terms of both the band structure of the electrodes, and the molecular electronic states of the clusters as modified by the lead environment. In addition, the quantum transport properties of Si nanoclusters doped with a Na atom are also analyzed.