Quantized conductance operation near a single-atom point contact in a polymer-based atomic switch

Abstract

Highly-controlled conductance quantization is achieved near a single-atom point contact in a redox-based atomic switch device, in which a poly(ethylene oxide) (PEO) film is sandwiched between Ag and Pt electrodes. Current–voltage measurements revealed reproducible quantized conductance of ∼1G0 for more than 102 continuous voltage sweep cycles under a specific condition, indicating the formation of a well-defined single-atom point contact of Ag in the PEO matrix. The device exhibited a conductance state distribution centered at 1G0, with distinct half-integer multiples of G0 and small fractional variations. First-principles density functional theory simulations showed that the experimental observations could be explained by the existence of a tunneling gap and the structural rearrangement of an atomic point contact.