Chirality and spin transformation of triplet Cooper pairs upon interaction with singlet condensate

Abstract

We show that the fully polarized triplet s-wave component is characterized not only by the spin direction, but also by chirality. Interaction of a polarized triplet component and a singlet one results in creation of triplet Cooper pairs with opposite spin direction or of different chiralities. Such spin transformation leads to interesting phenomena in multiterminal magnetic Josephson junctions. We calculate the dc Josephson current IJ in a multiterminal Josephson contact of the Sm/n/Sm′ type with “magnetic” superconductors Sm that generate fully polarized triplet components. The superconductors Sm are attached to magnetic insulators (filters) which let pass electrons with a fixed spin direction only. The filter axes are assumed to be oriented antiparallel to each other. The Josephson current is zero in two-terminal Josephson junction, i.e., in S/n/Sm or in Sm/n/Sm′ contact. But in the three-terminal Josephson junction, with another S superconductor attached to the normal wire, the finite current IJ appears flowing from the S superconductor to Sm superconductors. The currents through the right (left) superconductors Sm are opposite in sign, IR≡IJ=Icsin(χR+χL−2χ)=−IL, where χL/R and χ are the phases of superconductors Sm,Sm′, and S, respectively. We discuss possibilities of experimental observation of the effect.

Source-reported materials — not catalogue approval

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