Commensurability effects in large Josephson junctions

Very large thermophase in ferromagnetic Josephson junctions.

The concept of thermophase refers to the appearance of a phase gradient inside a superconductor originating from the presence of an applied temperature bias across it. The resulting supercurrent flow may, in suitable conditions, fully counterbalance the temperature-bias-induced quasiparticle current therefore preventing the formation of any voltage drop, i.e., a thermovoltage, across the superc...

Hysteresis in rf-driven large-area Josephson junctions.

Large Tunable Thermophase in Superconductor – Quantum Dot – Superconductor Josephson Junctions

In spite of extended efforts, detecting thermoelectric effects in superconductors has proven to be a challenging task, due to the inherent superconducting particle-hole symmetry. Here we present a theoretical study of an experimentally attainable Superconductor - Quantum Dot - Superconductor (SC-QD-SC) Josephson Junction. Using Keldysh Green's functions we derive the exact thermo-phase and ther...

Commensurability in One Dimension and the Josephson Junction Ladder

We study a Josephson junction ladder in a magnetic field in the absence of charging effects via a transfer matrix formalism. The eigenvalues of the transfer matrix are found numerically, giving a determination of the different phases of the ladder. The spatial periodicity of the ground state exhibits a devil’s staircase as a function of the magnetic flux filling factor f . If the transverse Jos...

Kinky Behavior in Josephson Junctions

We analyze nonperturbatively the behavior of a Josephson junction in which two BCS superconductors are coupled through an Anderson impurity. We recover earlier perturbative results which found that a δ = π phase difference is preferred when the impurity is singly occupied and the on-site Coulomb interaction is large. We find a novel intermediate phase in which one of δ = 0 and δ = π is stable w...