Multiple Chiral Majorana Fermion Modes and Quantum Transport

Abstract

We propose a general recipe for chiral topological superconductor (TSC) in two dimensions with multiple $N$ chiral Majorana fermion modes from a quantied anomalous Hall insulator in proximity to an s-wave superconductor with nontrivial band topology. A concrete example is that a $N=3$ chiral TSC may be realized by coupling a magnetic topological insulator and the ion-based superconductor such as FeTe$_{1-x}$Se$_{x}$ ($x=0.45$). We further propose the electrical and thermal transport experiments to detect the Majorana nature of three chiral edge fermions. A unique signature is that the two-terminal electrical conductance of a quantized anomalous Hall-TSC junction obeys a distribution averaged to $(2/3)e^2/h$, which is due to the random edge mode mixing of chiral Majorana fermions and is distinguished from possible trivial explanations.

5.2 pages, 4 figures, the conductance distribution is added