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arXiv · 1807.04841

Proximity-Induced Superconductivity at Non-Helical Topological Insulator Interfaces

David J. Alspaugh·Mahmoud M. Asmar·Daniel E. Sheehy·Ilya Vekhter
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Abstract

We study how non-helical spin textures at the boundary between a topological insulator (TI) and a superconductor (SC) affect the proximity-induced superconductivity of the TI interface state. We consider TIs coupled to both spin-singlet and spin-triplet SCs, and show that for the spin-triplet parent SCs the resulting order parameter induced onto the interface state sensitively depends on the symmetries which are broken at the TI-SC boundary. For chiral spin-triplet parent SCs, we find that nodal proximity-induced superconductivity emerges when there is broken twofold rotational symmetry which forces the spins of the non-helical topological states to tilt away from the interface plane. We furthermore show that the Andreev conductance of lateral heterostructures joining TI-vacuum and TI-SC interfaces yields experimental signatures of the reduced symmetries of the interface states.

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David J. Alspaugh, Mahmoud M. Asmar, Daniel E. Sheehy, Ilya Vekhter. 2018-07-12. Proximity-Induced Superconductivity at Non-Helical Topological Insulator Interfaces. https://doi.org/10.1103/physrevb.98.104516

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