Proximity-induced quasi-one-dimensional superconducting quantum anomalous Hall state: a promising scalable top-down approach towards localized Majorana modes

Abstract

In this work, ~100 nm wide quantum anomalous Hall insulator (QAHI) nanoribbons are etched from a two-dimensional QAHI film. One part of the nanoribbon is covered with superconducting Nb, while the other part is connected to an Au lead via two-dimensional QAHI regions. Andreev reflection spectroscopy measurements were performed, and multiple in-gap conductance peaks were observed in three different devices. In the presence of an increasing magnetic field perpendicular to the QAHI film, the multiple in-gap peak structure evolves into a single zero-bias conductance peak (ZBCP). Theoretical simulations suggest that the measurements are consistent with the scenario that the increasing magnetic field drives the nanoribbons from a multi-channel occupied regime to a single channel occupied regime, and that the ZBCP may be induced by zero energy Majorana modes as previously predicted [24]. Although further experiments are needed to clarify the nature of the ZBCP, we provide initial evidence that quasi-1D QAHI nanoribbon/superconductor heterostructures are new and promising platforms for realizing zero-energy Majorana modes.

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Cited by in corpus (8)

• Superconductivity and quantized anomalous Hall in rhombohedral graphene
• Robust Majorana bound states in magnetic topological insulator nanoribbons with fragile chiral edge channels
• Low-energy modeling of three-dimensional topological insulator nanostructures
• Inducing superconductivity in quantum anomalous Hall regime
• Optimizing proximitized magnetic topological insulator nanoribbons for Majorana bound states
• Laughlin charge pumping from interplay of chiral Dirac and chiral Majorana modes
• Symmetry-protected topological wire in a topological vacuum
• Electrostatic gating and the interference of chiral Majoranas in thin slabs of magnetic topological insulators