Multiple Andreev reflection in single atom niobium junctions

Abstract

Single atom junctions between superconducting niobium leads are produced using the Mechanically Controllable Break Junction technique. The current-voltage characteristics of these junctions are analysed using an exact formulation for a superconducting quantum point contact. For tunnelling 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 for these numbers are discussed.

11 pages; submitted to Phys. Rev. B

References in corpus (4)

• Microscopic origin of the conducting channels in metallic atomic-size contacts
• Resonant multiple Andreev reflections in mesoscopic superconducting junctions
• Superconducting d-wave junctions: The disappearance of the odd ac components
• Multiple Andreev reflections as a transport problem in energy space

Cited by in corpus (32)

• Quantum properties of atomic-sized conductors
• Andreev bound states in high-$T_c$ superconducting junctions
• Transparent Semiconductor-Superconductor Interface and Induced Gap in an Epitaxial Heterostructure Josephson Junction
• Universal features of electron-phonon interactions in atomic wires
• Dynamics and phonon-induced decoherence of Andreev level qubit
• Subharmonic Shapiro steps and assisted tunneling in superconducting point contacts
• Charge of a quasiparticle in a superconductor
• Theoretical study of the conductance of ferromagnetic atomic-sized contacts
• From favorable atomic configurations to supershell structures: a new interpretation of conductance histograms
• Transition from tunneling to direct contact in tungsten nanojunctions
• Resonant Andreev reflections in superconductor-carbon-nanotube devices
• DC-transport in superconducting point contacts: a full counting statistics view
• Keldysh study of point-contact tunneling between superconductors
• Coherent multiple Andreev reflections and current resonances in SNS junctions
• Subgap current in superconducting tunnel junctions with diffusive electrodes
• Subharmonic gap structures and Josephson effect in MgB2/Nb micro-constrictions
• Levitons in superconducting point contacts
• Subharmonic gap structure in superconducting scanning tunneling microscope junctions
• Dynamical Coulomb blockade of multiple Andreev reflections
• Analytic approach to transport in superconducting junctions with arbitrary carrier density
• Proximity Effect and Multiple Andreev Reflections in Chaotic Josephson junctions
• Coherent current transport in wide ballistic Josephson junctions
• Transient dynamics of a magnetic impurity coupled to superconducting electrodes: exact numerics versus perturbation theory
• Extracting the Transport Channel Transmissions in Scanning Tunneling Microscopy using the Superconducting Excess Current
• Breaking the quantum PIN code of atomic synapses
• Subharmonic Gap Structure in Superconductor/Ferromagnet/Superconductor Junctions
• ac Josephson effect in asymmetric superconducting quantum point contacts
• Influence of spin filtering and spin mixing on the subgap structure of I-V characteristics in superconducting quantum point contact
• Multiparticle tunneling in diffusive superconducting junctions
• Quantum transport properties of tantalum-oxide resistive switching filaments
• Nonequilibrium and relaxation effects in tunnel superconducting junctions
• ac Josephson effect in the resonant tunneling through mesoscopic superconducting junctions