Two mechanisms of Josephson phase shift generation by an Abrikosov vortex

Abstract

Abrikosov vortices contain magnetic fields and circulating currents that decay at a short range λ∼100 nm. However, vortices can induce Josephson phase shifts at a long range r∼μm≫λ. Mechanisms of this puzzling phenomenon are not clearly understood. Here we present a systematic study of vortex-induced phase shifts in planar Josephson junctions. We make two key observations: (i) The cutoff effect: Although vortex-induced phase shift is a long-range phenomenon, it is terminated by the junction and does not persist beyond it. (ii) A linear to superlinear crossover with a rapid upturn of the phase shift occurs upon approaching a vortex to a junction. The crossover occurs at a vortex-junction distance comparable to the penetration depth. Together with theoretical and numerical analysis this allows unambiguous identification of two distinct and independent mechanisms. The short range r≲λ mechanism is due to circulating vortex currents inside a superconducting electrode without involvement of magnetic fields. The long range r≫λ mechanism is due to stray magnetic fields outside electrodes without circulating vortex currents. We argue that understanding of controlling parameters of vortex-induced Josephson phase shift can be used for development of novel compact cryoelectronic devices.

Source-reported materials — not catalogue approval

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