1999/08/16 by B. Ludoph, N. van der Post, E. N. Bratus’ +8 · 7 citations
Engineering · Physics and Astronomy · #Molecular Junctions and Nanostructures #Quantum and electron transport phenomena #Surface and Thin Film Phenomena #cond-mat.mes-hall
paper · pdf · doi:10.1103/physrevb.61.8561
published as Phys. Rev. B 61, 8561 (2000) · 11 pages; submitted to Phys. Rev. B
arxiv created 1999/08/16 · openalex publication_date 2000/03/15 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Single-atom junctions between superconducting niobium leads are produced using the mechanically controllable break junction technique. The current-voltage characteristics of these junctions are analyzed using an exact formulation for a superconducting quantum point contact. For tunneling between two single atoms with a sufficiently large vacuum barrier, it is found that a single channel dominates the current, and that the current-voltage characteristic is described by the theory, without adjustable parameters. For a contact of a single Nb atom it is shown that five conductance channels contribute to the conductance, in agreement with the number expected based on the number of valence orbitals for this d metal. For each of the channels the transmission probability is obtained from the fits, and the limits of accuracy of these numbers are discussed.