Chiral topological superconductor and half-integer conductance plateau from quantum anomalous Hall plateau transition

TL;DR

This paper proposes creating a chiral topological superconductor from a quantum anomalous Hall system in a magnetic topological insulator, predicting a half-integer conductance plateau as a key experimental signature.

Contribution

It introduces a method to realize a chiral topological superconductor with a full bulk gap and a chiral Majorana edge mode using proximity effect in magnetic topological insulators.

Findings

Half-integer conductance plateau at coercive field

Conductance oscillates between e^2/2h and e^2/h in superconducting junctions

Feasibility of experimental detection discussed

Abstract

We propose to realize a two-dimensional chiral topological superconducting (TSC) state from the quantum anomalous Hall plateau transition in a magnetic topological insulator thin film through the proximity effect to a conventional $s$-wave superconductor. This state has a full pairing gap in the bulk and a single chiral Majorana mode at the edge. The optimal condition for realizing such chiral TSC is to have inequivalent superconducting pairing amplitudes on top and bottom surfaces of the doped magnetic topological insulator. We further propose several transport experiments to detect the chiral TSC. One unique signature is that the conductance will be quantized into a half-integer plateau at the coercive field in this hybrid system. In particular, with the point contact formed by a superconducting junction, the conductance oscillates between $e^2/2h$ and $e^2/h$ with the frequency determined by the voltage across the junction. We close by discussing the feasibility of these experimental proposals.