Electron standing-wave formation in atomic wires

Abstract

Using the Landauer formulation of transport theory and tight binding models\nof the electronic structure, we study electron transport through atomic wires\nthat form 1D constrictions between pairs of metallic nano-contacts. Our results\nare interpreted in terms of electron standing waves formed in the atomic wires\ndue to interference of electron waves reflected at the ends of the atomic\nconstrictions. We explore the influence of the chemistry of the atomic\nwire-metal contact interfaces on these standing waves and the associated\ntransport resonances by considering two types of atomic wires: gold wires\nattached to gold contacts and carbon wires attached to gold contacts. We find\nthat the conductance of the gold wires is roughly $1 G_0 = 2 e^2/h$ for the\nwire lengths studied, in agreement with experiments. By contrast, for the\ncarbon wires the conductance is found to oscillate strongly as the number of\natoms in the wire varies, the odd numbered chains being more conductive than\nthe even numbered ones, in agreement with previous theoretical work that was\nbased on a different model of the carbon wire and metal contacts.\n

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Affiliated Institutions

• Simon Fraser University CA

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