Regensburg 2022 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 32: Focus Session: Topological Devices (joint session TT/KFM)

TT 32.2: Hauptvortrag

Donnerstag, 8. September 2022, 15:30–16:00, H10

Majorana bound states and non-reciprocal transport in topological insulator nanowire devices — •Henry Legg — Department of Physics, University of Basel

I consider devices consisting of a three-dimensional topological insulator (TI) nanowire placed in proximity to an s-wave superconductor.

First, I will show that a non-uniform chemical potential induced, for instance, by gating enables the device to be brought into a topological superconducting phase at relatively weak magnetic fields with Majorana bound states (MBSs) present for an exceptionally large region of parameter space in realistic systems. I also consider the experimental challenges posed by the metallization effect that occurs as a result of bringing a TI nanowire into proximity with a superconductor.

Second, I will discuss non-reciprocal transport evidence for the subband splitting that is central to the proposal to achieve MBSs in TI nanowires. I will show that a giant magnetochiral anisotropy observed in the normal state of the TI nanowire provides strong evidence for the artificial breaking of inversion symmetry due to gating effects. Furthermore, I will argue that the superconducting diode effect can be used as measure of inversion symmetry breaking in the presence of a superconductor and to determine when the TI nanowire is in the region of parameter space where topological superconductivity is expected.