Superconducting proximity effect and Majorana flat bands in the surface of a Weyl semimetal

TL;DR

This paper investigates the proximity effect between an s-wave superconductor and Weyl semimetal surface states, revealing flat Majorana bands in a Josephson junction, with discussions on their stability and experimental detection.

Contribution

It introduces a novel interface superconductor in Weyl semimetals supporting flat Majorana bands, differing from Fu-Kane superconductors, and analyzes their stability and observability.

Findings

Flat Majorana bands appear in the Josephson junction with a π phase difference.

The interface superconductor exhibits properties similar to Fu-Kane superconductor.

Proposed experimental methods for observing the Majorana flat bands.

Abstract

We study the proximity effect between an s-wave superconductor (SC) and the surface states of a Weyl semimetal. An interesting two-dimensional SC forms in such an interface with properties resembling in certain aspects the Fu-Kane superconductor with some notable differences. In a Weyl semimetal with unbroken time reversal symmetry the interface SC supports completely flat Majorana bands in a linear Josephson junction with a {\pi} phase difference. We discuss stability of these bands against disorder and propose ways in which they can be observed experimentally.