Towards a robust Majorana platform based on magnetic topological insulator nanoribbons*

Magnetic topological insulators (MTIs) are promising materials for realizing a topological phase with Majoranas (propagating edge modes and end-localized bound states) when combining them with proximity-induced superconductivity. With detailed simulations, we investigate Majoranas in realistic MTI nanoribbons covered by a superconductor. We find that both end-localized and propagating Majoranas can be realized in such a structure, and that they give rise to distinct transport signatures in normal-superconductor (NS) or NSN junctions. We also study the impact of disorder and, while the quantum anomalous Hall edge channels of a MTI nanoribbon are quite fragile, the topological phase appears to be robust. This robustness can be confirmed by comparing the tunneling conductance at the end of a proximitized MTI nanoribbon to normal transport in a comparable MTI device without superconductor on top. Finally, we report on the latest status on our experimental platform towards MTI-based Majorana devices, based on an in situ nanofabrication process.