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TT: Fachverband Tiefe Temperaturen

TT 108: Topological Superconductors

TT 108.2: Vortrag

Freitag, 16. März 2018, 09:45–10:00, H 2053

Tunabale hybridization of Majorana bound states at the quantum spin Hall edge — •Felix Keidel¹, 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

We study the helical edge of a quantum spin Hall insulator in proximity to an s-wave superconductor (S) and ferromagnetic insulators (F). Hybrid structures of this kind are known to give rise to topological superconductivity and allow for Majorana bound states in regions where both the ferromagnetic and the superconducting gap close. This can be used to localize and couple Majorana modes.

In our work, we consider junctions with alternating S and F barriers and a system with three S barriers. The cavities between them can be understood as quantum dots hosting overlapping Majorana (MBS) and Andreev quasi-bound states (ABS). We demonstrate how the resulting hybridization and splitting depend on distinct parameters of the systems. Remarkably, we can make a close connection between the localized bound states and the induced nonlocal pairing amplitudes. The anomalous correlations provide a way to distinguish MBS and ABS and exhibit odd-frequency dominated triplet pairing for resonances associated with hybridized MBS.