Abstract
We investigate spin-dependent quasiparticle and Cooper-pair transport through a central node interfaced with two superconductors and two ferromagnets. We demonstrate that voltage biasing of the ferromagnetic contacts induces superconducting triplet correlations on the node and reverses the supercurrent flowing between the two superconducting contacts. We further find that such triplet correlations can mediate a tunable spin current flow into the ferromagnetic contacts. Our key finding is that unequal spin-mixing conductances for the two interfaces with the ferromagnets result in equal-spin triplet correlations on the node, detectable via a net charge current between the two magnets. Our proposed device thus enables the generation, control, and detection of the typically elusive equal-spin triplet Cooper pairs.
Highlights
Cooper pairs from a superconductor (S) placed in the vicinity of a ferromagnet (F) may diffuse into the latter, modifying their electronic properties [1,2,3,4,5]
We demonstrate that voltage biasing of the ferromagnetic contacts induces superconducting triplet correlations on the node and reverses the supercurrent flowing between the two superconducting contacts
While a ground state at zero phase difference indicates a Josephson current mediated by singlet Cooper pairs, a shifted ground state about π, occurring in magnetic Josephson junctions [35,36,37,38,39,40,41,42,43,44], signals triplet superconductivity [45,46,47,48] manifesting in a reversed current phase relation (CPR) [49,50,51]
Summary
Cooper pairs from a superconductor (S) placed in the vicinity of a ferromagnet (F) may diffuse into the latter, modifying their electronic properties [1,2,3,4,5]. While a ground state at zero phase difference indicates a Josephson current mediated by singlet Cooper pairs, a shifted ground state about π , occurring in magnetic Josephson junctions [35,36,37,38,39,40,41,42,43,44], signals triplet superconductivity [45,46,47,48] manifesting in a reversed current phase relation (CPR) [49,50,51]. It is the immunity of equalspin-triplet correlations against internal magnetic fields which causes a long penetration length into ferromagnets compared to the ones of singlet and mixed-triplet correlations [61,62,63] This property of equal-spin-triplet pairs makes them particular attractive for low-power spintronics [64,65,66]. Its multiterminal topology allows the currents to be channeled in various ways, making it a potential building block for future superconducting spintronics technologies [64,65]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
