Regensburg 2010 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 7: SC: Heterostructures, Andreev Scattering, Proximity Effect, Coexistence

TT 7.3: Talk

Monday, March 22, 2010, 14:30–14:45, H20

Charge and spin currents in a triplet superconductor-ferromagnet-singlet superconductor Josephson junction — Yasuhiro Asano¹, •Dirk Manske², and Philip Brydon³ — ¹Department of Applied Physics, Hokkaido University — ²Max Planck Institute for Solid State Research — ³Institute for Theoretical Physics, TU Dresden

The study of triplet superconductor Josephson junctions with magnetically-active tunneling barriers has revealed an intimate connection between charge and spin supercurrents in these devices [1,2]. Here we generalize this analysis to tunneling between a spin-triplet and a spin-singlet superconductor through a magnetic barrier. Using a tunneling Hamiltonian analysis, we show how spin-flip tunneling processes produce a lowest-order Josephson coupling between the two superconductors, accomplishing both spin- and orbital-parity conversion for the tunneling Cooper pairs. Remarkably, in the triplet superconductor the charge current is accompanied by a phase-dependent spin current. We verify these predictions using a Bogoliubov-de Gennes technique, which reveals the importance of the orbital pairing state of the two superconductors for the appearance of these effects.

[1] P. M. R. Brydon, D. Manske, and M. Sigrist, J. Phys. Soc. Japan 77, 103714 (2008).

[2] P. M. R. Brydon and D. Manske, Phys. Rev. Lett. 103, 147001 (2009).