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HL: Fachverband Halbleiterphysik
HL 7: (Quantum) Transport Properties
HL 7.4: Vortrag
Montag, 5. September 2022, 15:45–16:00, H31
Tunneling spectroscopy simulations of topological insulator (TI) nanoribbons — •Dennis Heffels1, Declan Burke2, Malcolm R. Connolly2, Peter Schüffelgen1, Kristof Moors1, and Detlev Grützmacher1 — 1PGI-9, FZ Jülich — 2IC London
TI nanoribbons with proximity-induced superconductivity have been proposed as a possible platform for the realization of Majorana bound states (MBS). Attempts to detect these MBS have received much attention in solid-state physics in recent years. A major goal is to exploit their unusual non-Abelian statistics for topologically protected quantum computing. A very common method for the detection of MBS is tunneling spectroscopy. Implementing this experimental scheme with TI nanoribbons is very challenging, due to stringent requirements on the interfaces of the required heterostructure. Similar experiments on semiconductor nanowires have shown that careful interpretation of the measured data is of prime importance. Here, we present simulations that are tailored to support such tunneling spectroscopy experiments on TI nanoribbons that are proximitized via the top surface with a superconductor. We show that a 3D simulation of the TI-based tunnel junction device is essential to properly describe the proximity effect and disorder, which plays a crucial role. Interestingly, the absence or presence of a zero-bias conductance peak does not always reveal whether the system is in the trivial or the topological regime. We obtain a phase diagram of subgap features in the tunneling conductance as a function of magnetic field and Fermi level.