Magnon-Cooparons in magnet-superconductor hybrids

I. V. Bobkova; A. M. Bobkov; Akashdeep Kamra; Wolfgang Belzig

doi:10.1038/s43246-022-00321-8

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arXiv · 2203.05336

Magnon-Cooparons in magnet-superconductor hybrids

I. V. Bobkova·A. M. Bobkov·Akashdeep Kamra·Wolfgang Belzig

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Abstract

Generation and detection of spinful Cooper pairs in conventional superconductors has been intensely pursued by designing increasingly complex magnet-superconductor hybrids. Here, we demonstrate theoretically that magnons with nonzero wavenumbers universally induce a cloud of spinful triplet Cooper pairs around them in an adjacent conventional superconductor. The resulting composite quasiparticle, termed magnon-cooparon, consists of a spin flip in the magnet screened by a cloud of the spinful superfluid condensate. Thus, it inherits a large effective mass, which can be measured experimentally. Furthermore, we demonstrate that two magnetic wires deposited on a superconductor serve as a controllable magnonic directional coupler mediated by the nonlocal and composite nature of magnon-cooparons. Our analysis predicts a quasiparticle that enables generation, control, and use of spinful triplet Cooper pairs in the simplest magnet-superconductor heterostructures.

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I. V. Bobkova, A. M. Bobkov, Akashdeep Kamra, Wolfgang Belzig. 2022-03-10. Magnon-Cooparons in magnet-superconductor hybrids. https://doi.org/10.1038/s43246-022-00321-8

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