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In the theoretical study of Josephson junctions, it is usually assumed that the properties of the tunneling barrier are fixed. This assumption breaks down when considering tunneling between two triplet superconductors with misaligned d-vectors. Such a situation breaks time-reversal symmetry, which permits the stabilization of a magnetic moment at the tunneling barrier. This radically alters the behaviour of the junction, stabilizing it in a
fractional state, i.e. the free energy minimum lies at a phase difference intermediate between 0 and π. Fractional flux quanta are then permitted at the junction. A further consequence of the d-vector misalignment is the appearance of a Josephson spin current, which flows even in the absence of an equilibrium charge
current. We demonstrate these effects on the prototype of a triplet Josephson junction, the so-called TFT-junction (T = triplet superconductor, F = Ferromagnet) [1-3].
[1] P.M.R. Brydon, C. Iniotakis, D. Manske, and M. Sigrist, Phys. Rev. Lett. 104, 197001 (2010). [2] P.M.R. Brydon and D. Manske, Phys. Rev. Lett. 103, 147001 (2009) [3] P.M.R. Brydon, C. Iniotakis, and D. Manske, New J. Phys. 11, 055055 (2009). |
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