Enhanced Triplet Pairing in Magnetic Junctions with s-wave Superconductors

A common path to Majorana fermions and topologically-protected quantum computing relies on spin-triplet superconductivity[1]. While spin-triplet pairing is elusive in nature and even common spin-triplet candidates, such as Sr2RuO4, could support alternative explanations[2], proximity effects in heterostructures can overcome these limitations. Specifically, a common expectation is that robust spin-triplet superconductivity in magnetic junctions should rely on highly spin-polarized magnets or complex magnetic multilayers[3]. Instead, we predict that the interplay of interfacial spin-orbit coupling and the barrier strength in simple magnetic junctions with s-wave superconductors can lead to nearly complete spin-triplet superconducting proximity effects when magnets have only a small spin polarization. We show that this enhanced spin-triplet regime is characterized by a huge increase in conductance magnetoanisotropy[4], orders of magnitude larger than in the normal state.

We thank P. Hoegl for valuable discussions.

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[2] I. Zutić, I. Mazin, PRL 95, 217004 (2005)
[3] M. Eschrig, Phys. Today 64, 43 (2011)
[4] P. Högl, A. Matos-Abiague, I. Zutić, J. Fabian, PRL 115, 116601(2015)