Magnetic interference patterns in superconducting junctions: Effects of anharmonic current-phase relations

Abstract

A microscopic theory of the magnetic-field modulation of critical currents is developed for plane Josephson junctions with anharmonic current-phase relations. The results obtained allow examining temperature-dependent deviations of the modulation from the conventional interference pattern. For tunneling through localized states in symmetric short junctions with a pronounced anharmonic behavior, the deviations are obtained and shown to depend on distribution of channel transparencies. For constant transparency the deviations vanish not only near Tc, but also at T = 0. If Dorokhov bimodal distribution for transparency eigenvalues holds, the averaged deviation increases with decreasing temperature and takes its maximum at T = 0.

Modeling of vortex dynamics in HTSs with defects under the impact of pulsed magnetic field

“…Those are, for example, the superconductor-ferromagnet-superconductor (S/F/S) junctions [25] (and the more complex S-Ho/N/Ho-S contacts [26] where N is the normal (non-superconducting) phase), the S/TI/S (where TI stands for topological insulator) [27] and S/Ws/S (where Ws is the Weyl semimetal) [28] contacts, as well as elliptical annular junctions [29,30]. Recent studies have shown that anharmonic relations between the supercurrent and phase occur in junctions with strong Josephson coupling, causing the vortices to increase in size [31][32][33]. In all the mentioned cases, circular currents with normal centers appeared in the non-superconducting phase.…”

φ-state and inverted Fraunhofer pattern in nonaligned Josephson junctions

“…Nevertheless, several theoretical studies have been dedicated to the aim of achieving an experimentally accessible situation where the CPR is non-sinusoidal [6][7][8] . In this case, the Josephson ground-state may be characterized by an arbitrary superconducting phase difference ϕ [6][7][8]21,23 , rather than the socalled 0and π-states 9 . The first experimental realization of such a ϕ-junction was very recently reported in Ref.…”

“…Recent studies have also pointed to the fact that the conventional Fraunhofer pattern in Josephson junctions may be modified by the junction geometry or interfacial pair breaking 4,10,21 . The suppression of the central peak in the interference pattern can also occur in systems consisting of a superposition of multiple 0-π junctions 8,10,21 .…”

“…Recent studies have also pointed to the fact that the conventional Fraunhofer pattern in Josephson junctions may be modified by the junction geometry or interfacial pair breaking 4,10,21 . The suppression of the central peak in the interference pattern can also occur in systems consisting of a superposition of multiple 0-π junctions 8,10,21 . However, there still exists experimentally observed magnetic interference profiles that remain unsettled in terms of a theoretical explanation of the physical origin 11,12 .…”

Non-Fraunhofer patterns of the anharmonic Josephson current influenced by strong interfacial pair breaking

“…Here ℓ B = ( c/|eB(0)|) 1/2 is the magnetic length. With this relation, the Josephson current averaged over the interface is [26]…”