Spontaneous vortex state and -junction in a superconducting bijunction with a localized spin
arXiv:1405.6889 · doi:10.1103/PhysRevB.90.075432
Abstract
A Josephson bijunction made of three superconductors connected by a quantum dot is considered in the regime where the dot carries a magnetic moment. In the range of parameters where such a dot, if inserted in a two-terminal Josephson junction, creates a -shift of the phase, the bijunction forming a triangular unit is frustrated. This frustration is studied both within a phenomenological and a microscopic model. Frustration stabilizes a phase vortex centered on the dot, with two degenerate states carrying opposite vorticities, independently of the direction of the magnetic moment. Embedding the bijunction in a superconducting loop allows to create a tunable ""-junction whose equilibrium phase can take any value. For large enough inductance, it generates noninteger spontaneous flux. Multi-loop configurations are also studied.
References in corpus (12)
- Tunable Supercurrent Through Semiconductor Nanowires
- Supercurrent reversal in quantum dots
- Quantum supercurrent transistors in carbon nanotubes
- Anomalous Josephson Current in Junctions with Spin-Polarizing Quantum Point Contacts
- Josephson junctions with negative second harmonic in the current-phase relation: properties of novel varphi-junctions
- 0-pi Josephson tunnel junctions with ferromagnetic barrier
- Transport Through Andreev Bound States in a Graphene Quantum Dot
- Experimental evidence of a ϕ Josephson junction
- Charge transport through single molecules, quantum dots, and quantum wires
- Spin-orbit induced chirality of Andreev states in Josephson junctions
- φ-State and Inverted Fraunhofer Pattern in Nonaligned Josephson Junctions
- Controllable pi junction in a Josephson quantum-dot device with molecular spin