Coherent transport properties of a three-terminal hybrid superconducting interferometer

Abstract

Coherent transport properties of a three-terminal hybrid superconducting interferometerVischi, F.; Carrega, M.; Strambini, E.; D'Ambrosio, S.; Bergeret, F. S.; Nazarov, Yuli; Giazotto, F. Important noteTo cite this publication, please use the final published version (if applicable). Please check the document version above. CopyrightOther than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons. Takedown policyPlease contact us and provide details if you believe this document breaches copyrights. We will remove access to the work immediately and investigate your claim. We present an exhaustive theoretical analysis of a double-loop Josephson proximity interferometer, such as the one recently realized by Strambini et al. for control of the Andreev spectrum via an external magnetic field. This system, called ω-SQUIPT, consists of a T-shaped diffusive normal metal (N ) attached to three superconductors (S) forming a double-loop configuration. By using the quasiclassical Green-function formalism, we calculate the local normalized density of states, the Josephson currents through the device, and the dependence of the former on the length of the junction arms, the applied magnetic field, and the S/N interface transparencies. We show that by tuning the fluxes through the double loop, the system undergoes transitions from a gapped to a gapless state. We also evaluate the Josephson currents flowing in the different arms as a function of magnetic fluxes, and we explore the quasiparticle transport by considering a metallic probe tunnel-coupled to the Josephson junction and calculating its I -V characteristics. Finally, we study the performances of the ω-SQUIPT and its potential applications by investigating its electrical and magnetometric properties.

Supercurrent Flow in Multiterminal Graphene Josephson Junctions

“…On the experimental side, topological properties of multi-terminal structures have been investigated in Refs. [15,16]. Elsewhere, it has been reported that complex spectra of Andreev reflections could originate from non-local entanglement of two or more Cooper pairs in three or more leads [17][18][19][20].…”

“…Finally the effects of the dissipative current on the magnitude of the supercurrent can be accounted for by self-heating in the device. Our experiment opens the prospects for future search of topological effects in multi-terminal graphene devices [11][12][13][14][15][16].…”

Anomalous current in diffusive ferromagnetic Josephson junctions

“…(10) and (11), we see that, in principle, I (ϕ,h, P) = −I (−ϕ,h, P) and the zero-phase-difference current at ϕ = 0 is not prohibited by symmetry. From this simple analysis it is clear that the general features of the CPR can be deduced from the symmetry relations (10) and (11). First, we consider the S/FI/F/FI/S structure of Fig.…”

“…In certain cases, however, I c < 0, and the ground state corresponds to ϕ = π . Such π junctions can be realized, for example, in superconductor/ferromagnet/superconductor (S/F/S) structures [3][4][5][6], Josephson junctions with nonequilibrium normal metal interlayer [7], d-wave superconductors [8], semiconductor nanowires [9], gated carbon nanotubes [10], and multiterminal Josephson systems [11]. The π junctions have been suggested for building scalable superconducting digital and quantum logic [12][13][14].…”

Topological SQUIPT Based on Helical Edge States in Proximity to Superconductors

“…1. In essence the proposed device realizes a Topological variant of the Superconducting Quantum Interference Proximity Transistor [59][60][61][62][63][64][65][66][67][68][69][70][71][72][73] or TSQUIPT. We characterize the TSQUIPT and its performance, and present calculations of the expected device behavior in transport experiments.…”