Spontaneous vortex state and phi-junction in a superconducting bijunction with a localized spin

Article

关键词: CARBON NANOTUBES;    QUANTUM-DOT;    JOSEPHSON-JUNCTIONS;    SUPERCURRENT;    TRANSPORT;    DEVICES;   

DOI  :  10.1103/PhysRevB.90.075432

来源: SCIE

【 摘 要 】

A Josephson bijunction made of three superconductors connected by a quantum dot is considered in the regime where the dot carries amagnetic moment. In the range of parameters where such a dot, if inserted in a two-terminal Josephson junction, creates a pi-shift of the phase, the bijunction forming a triangular unit is frustrated. This frustration is studied within both 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 one to create a tunable phi-junction whose equilibrium phase can take any value. For large enough inductance, it generates noninteger spontaneous flux. Multiloop configurations are also studied.

【 授权许可】

Free