Controllable pi junction in a Josephson quantum-dot device with molecular spin

Abstract

We consider a model for a single molecule with a large frozen spin sandwiched in between two BCS superconductors at equilibrium, and show that this system has a $\pi$ junction behavior at low temperature. The $\pi$ shift can be reversed by varying the other parameters of the system, e.g., temperature or the position of the quantum dot level, implying a controllable $\pi$ junction with novel application as a Josephson current switch. We show that the mechanism leading to the $\pi$ shift can be explained simply in terms of the contributions of the Andreev bound states and of the continuum of states above the superconducting gap. The free energy for certain configuration of parameters shows a bistable nature, which is a necessary pre-condition for achievement of a qubit.

References in corpus (20)

• Proximity effects in superconductor-ferromagnet heterostructures
• Coupling of two superconductors through a ferromagnet : evidence for a pi-junction
• Measurement of the conductance of a hydrogen molecule
• Phonon effects in molecular transistors: Quantum and classical treatment
• Quiet SDS Josephson Junctions for Quantum Computing
• Superconductivity in Ropes of Single-Walled Carbon Nanotubes
• Coulomb blockade at almost perfect transmission
• Enhancement of the Josephson current by an exchange field in superconductor-ferromagnet structures
• Josephson Current through a correlated quantum level: Andreev states and Pi-junction behavior
• Kinky Behavior in Josephson Junctions
• Degenerate ground state in a mesoscopic YBaCuO grain boundary Josephson junction
• Josephson current through a nanoscale magnetic quantum dot
• Coulomb Blockade without Tunnel Junctions
• Supercurrent-carrying density of states in diffusive mesoscopic Josephson weak links
• Novel Spin Dynamics in a Josephson Junction
• Proximity Effect in a Superconductor-Metallofullerene-Superconductor Molecular Junction
• Novel Josephson Effect in Triplet Superconductor - Ferromagnet - Triplet Superconductor Junctions
• Interplay between Josephson effect and magnetic interactions in double quantum dots
• Theoretical description of the ferromagnetic $\pi$-junctions near the critical temperature
• Spectrum and thermodynamic currents in one dimensional Josephson elements

Cited by in corpus (30)

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• Self-consistent description of Andreev bound states in Josephson quantum dot devices
• A weak coupling CTQMC study of the single impurity and periodic Anderson models with s-wave superconducting baths
• Interaction of a Nanomagnet with a Weak Superconducting Link
• Nonsinusoidal current-phase relations in semiconductor-superconductor-ferromagnetic insulator devices
• Manipulation with Andreev states in spin active mesoscopic Josephson junctions
• Phase Controllable Josephson Junctions for Cryogenic Memory
• Josephson effect through a quantum dot array
• Non-equilibrium supercurrent through a quantum dot: current harmonics and proximity effect due to a normal metal lead
• Magneto-electric spectroscopy of Andreev bound states in Josephson quantum dots
• Transport and magnetization dynamics in a superconductor/single-molecule magnet/superconductor junction
• Washing out of the 0-pi transition in Josephson junctions
• Kondo screening of Andreev bound states in an N-QD-S system
• Single magnetic molecule between conducting leads: Effect of mechanical rotations
• Josephson effect through an anisotropic magnetic molecule
• Polaron effects on the dc- and ac-tunneling characteristics of molecular Josephson junctions
• Quartets and the Current-Phase Structure of a Double Quantum Dot Superconducting Bijunction at Equilibrium
• Josephson current through a quantum dot coupled to a molecular magnet
• Andreev non-Hermitian Hamiltonian for open Josephson junctions from Green's functions
• $\pi$-junction qubit in monolayer graphene
• Tuning the 0$-\pi$ Josephson junction with a magnetic impurity: Role of tunnel contacts, exchange coupling, $e-e$ interactions and high-spin states
• Non local Andreev reflection in a carbon nanotube superconducting quantum interference device
• Spontaneous vortex state and $\phi$-junction in a superconducting bijunction with a localized spin
• Strain designed Josephson $\pi$ junction qubits with topological insulators
• Andreev spin-noise detector
• Supercurrent from the imaginary part of the Andreev levels in non-Hermitian Josephson junctions
• Quantum phase transitions in superconductor--quantum-dot--superconductor Josephson structures with attractive intradot interaction
• Magnetic flux controlled current phase relationship in double Quantum Dot Josephson junction
• Slave-spin approach to the Anderson-Josephson quantum dot
• Quantum phase transition in a double quantum dot Josephson junction driven by electron-electron interactions