Conductance oscillations and speed of chiral Majorana mode in a quantum-anomalous-Hall 2d strip

TL;DR

This paper predicts conductance oscillations in a quantum-anomalous Hall 2D strip with a superconducting region, which can be used to measure the speed of chiral Majorana modes through interference effects.

Contribution

It introduces a method to determine the speed of chiral Majorana modes via conductance oscillations in a quantum-anomalous Hall device with a superconducting segment.

Findings

Conductance oscillations depend on the length of the superconducting region and transverse size.

Oscillation periodicity reveals the speed of chiral Majorana modes.

Interference effects are enhanced by side barriers.

Abstract

We predict conductance oscillations in a quantum-anomalous Hall 2d strip having a superconducting region of length $L_x$ with a chiral Majorana mode. These oscillations require a finite transverse extension of the strip $L_y$ of a few microns or less. Measuring the conductance periodicity with $L_x$ and a fixed bias, or with bias and a fixed $L_x$, yields the speed of the chiral Majorana mode. The physical mechanism behind the oscillations is the interference between backscattered chiral modes from second to first interface of the NSN double junction. The interferometer effect is enhanced by the presence of side barriers.