Closing the proximity gap in a metallic Josephson junction between three superconductors

Abstract

We describe the proximity effect in a short disordered metallic junction between three superconducting leads. Andreev bound states in the multi-terminal junction may cross the Fermi level. We reveal that for a quasi-continuous metallic density of states, crossings at the Fermi level manifest as closing of the proximity-induced gap. We calculate the local density of states for a wide range of transport parameters using quantum circuit theory. The gap closes inside an area of the space spanned by the superconducting phase differences. We derive an approximate analytic expression for the boundary of the area and compare it to the full numerical solution. The size of the area increases with the transparency of the junction and is sensitive to asymmetry. The finite density of states at zero energy is unaffected by electron-hole decoherence present in the junction, although decoherence is important at higher energies. Our predictions can be tested using tunneling transport spectroscopy. To encourage experiments, we calculate the current-voltage characteristic in a typical measurement setup. We show how the structure of the local density of states can be mapped out from the measurement.

8 pages, 7 figures

References in corpus (10)

• Superconducting proximity effect and Majorana fermions at the surface of a topological insulator
• Signatures of Majorana fermions in hybrid superconductor-semiconductor nanowire devices
• Evidence for crossed Andreev reflection in superconductor-ferromagnet hybrid structures
• Single fermion manipulation via superconducting phase differences in multiterminal Josephson junctions
• Production of non-local quartets and phase-sensitive entanglement in a superconducting beam splitter
• Singularities of Andreev spectrum in multi-terminal Josephson junction
• Circuit theory of crossed Andreev reflection
• Spin-blockade qubit in a superconducting junction
• Proposal for the observation of nonlocal multipair production: the biSQUID
• Quartets and the Current-Phase Structure of a Double Quantum Dot Superconducting Bijunction at Equilibrium

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