Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 108: Topological Superconductors
TT 108.7: Vortrag
Freitag, 16. März 2018, 11:15–11:30, H 2053
Creation of spin-triplet Cooper pairs in the absence of magnetic ordering — •Daniel Breunig1, Pablo Burset2, and Björn Trauzettel1 — 1Institute for Theoretical Physics and Astrophysics, *University of Würzburg, D-97074 Würzburg, Germany — 2Department of Applied Physics, Aalto University, FIN-00076 Aalto, Finland
In superconducting spintronics, it is essential to generate spin-triplet Cooper pairs on demand. Up to now, proposals to do so concentrate on hybrid structures in which a superconductor (SC) is combined with a magnetically ordered material (or an external magnetic field). We, instead, identify a novel way to create and isolate spin-triplet Cooper pairs in the absence of any magnetic ordering. This achievement is only possible because we drive a system with strong spin-orbit interaction--the Dirac surface states of a strong topological insulator (TI)--out of equilibrium. In particular, we consider a bipolar TI-SC-TI junction, where the electrochemical potentials in the outer leads differ in their overall sign. As a result, we find that nonlocal singlet pairing across the junction is completely suppressed for any excitation energy. Hence, this junction acts as a perfect spin triplet filter across the SC generating equal-spin Cooper pairs via crossed Andreev reflection.