Revealing the Geometry and Conductance of Double-Stranded Atomic Chains of Gold

Abstract

Here we report on the identification and characterization of suspended double-stranded Au atomic chains up to ∼4 atoms long, using a scanning tunneling microscope adapted for the fabrication and simultaneous recording of the conductance. These chains are one of the smallest structures with the highest stability connecting two metallic electrodes, identified from the evolution of the conductance in the process of the controlled breakage of the contact between two metals. Molecular dynamics simulations and density functional theory electron transport calculations help us to unveil the richness of the geometric structures appearing in the experiments in the form of double-stranded chains, their stability, and how these can evolve into the formation of monoatomic chains.