114 research outputs found

    Josephson effect through magnetic skyrmion

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    We discover that the multiple degrees of freedom associated with magnetic skyrmions: size, position, and chirality, can all be used to control the Josephson effect and 0-pi transitions occurring in superconductor/magnetic skyrmion/superconductor junctions. In the presence of two skyrmions, the Josephson effect depends strongly on their relative chirality and leads to the possibility of a chirality-transistor effect for the supercurrent where the critical current is changed by several orders of magnitude simply by reversing the chirality of a magnetic skyrmion. Moreover, we demonstrate that the Fraunhofer pattern can show a local minimum at zero flux as a direct result of the skyrmion magnetic texture. These findings demonstrate the rich physics that emerges when combining topological magnetic objects with superconductors and could lead to new perspectives in superconducting spintronics.Comment: 5 pages, 5 figure

    Superconducting Proximity Effect in Silicene: Spin-Valley Polarized Andreev Reflection, Non-Local Transport, and Supercurrent

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    We theoretically study the superconducting proximity effect in silicene, which features massive Dirac fermions with a tunable mass (band gap), and compute the conductance across a normal/superconductor (N/S) silicene junction, the non-local conductance of an N/S/N junction, and the supercurrent flowing in an S/N/S junction. It is demonstrated that the transport processes consisting of local and non-local Andreev reflection may be efficiently controlled via an external electric field owing to the buckled structure of silicene. In particular, we demonstrate that it is possible to obtain a fully spin-valley polarized crossed Andreev reflection process without any contamination of elastic cotunneling or local Andreev reflection, in stark contrast to ordinary metals. It is also shown that the supercurrent flowing in the S/N/S junction can be fully spin-valley polarized and that it is controllable by an external electric field.Comment: 5 pages, 4 figures + supplementary informatio

    Anisotropic Paramagnetic Meissner Effect by Spin-Orbit Coupling

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    Conventional ss-wave superconductors repel external magnetic flux. However, a recent experiment [A. Di Bernardo et al., Phys. Rev. X \textbf{5}, 041021 (2015)] has tailored the electromagnetic response of superconducting correlations via adjacent magnetic materials. We consider another route to alter the Meissner effect where spin-orbit interactions induce an anisotropic Meissner response that changes sign depending on the field orientation. The tunable electromagnetic response opens new paths in the utilization of hybrid systems comprised of magnets and superconductors.Comment: 5 pages, 3 figures. Accepted for publication in Phys. Rev. Let
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