Inducing superconductivity in quantum anomalous Hall regime

TL;DR

This paper demonstrates the successful induction of topological superconductivity in a quantum anomalous Hall insulator by carefully controlling the interface with a superconductor, addressing previous experimental challenges.

Contribution

It provides a detailed interface control method and a phase diagram that explains how to reliably realize topological superconductivity via proximity effect.

Findings

Reproduced topological superconductor with conductance matching theoretical predictions.

Developed a phase diagram showing parameter regions for topological superconductivity.

Clarified the role of interface control in achieving topological superconductivity.

Abstract

Interfacing the quantum anomalous Hall insulator with a conventional superconductor is known to be a promising manner for realizing a topological superconductor, which has been continuously pursued for years. Such a proximity route depends to a great extent on the control of the delicate interfacial coupling of the two constituents. However, a recent experiment reported the failure to reproduce such a topological superconductor, which is ascribed to the negligence of the electrical short by the superconductor in the theoretical proposal. Here, we reproduce this topological superconductor with attention to the interface control. The resulted conductance matrix under a wide magnetic field range agrees with the fingerprint of this topological superconductor. This allows us to develop a phase diagram that unveils three regions parameterized by various coupling limits, which not only supports the feasibility to fabricate the topological superconductor by proximity but also fully explains the origin of the previous debate. The present work provides a comprehensible guide on fabricating the topological superconductor.