# Induced superconductivity in Fermi arcs

## TL;DR

This paper explores how superconductivity induces unique topological features like Bogoliubov Fermi contours in Weyl semimetals with Fermi arcs, revealing novel transport and spectroscopic signatures.

## Contribution

It demonstrates the emergence of a $Z_2$ protected Bogoliubov Fermi contour and Majorana Fermi surface in superconductor-Weyl semimetal interfaces, highlighting their topological and spectroscopic properties.

## Key findings

- Presence of a $Z_2$ protected Bogoliubov Fermi contour with linear dispersion.
- Distinct $T^2$ temperature dependence in specific heat contributions.
- Zero-bias peak in tunneling spectra related to Majorana Fermi surface.

## Abstract

When the interface of a superconductor (SC) with Weyl semimetal (WSM) supports Fermi arcs, the chirality blockade eliminates the induction of superconductivity into the bulk. This leaves the Fermi arc states as the only low-energy degrees of freedom in the proximity problem. Therefore the SC|WSM system will be a platform to probe transport properties that only involve the Fermi arcs. With a boundary condition that flips the spin at the boundary, we find a $Z_2$ protected Bogoliubov Fermi contour (BFC) around which the Bogoliubov quasi-particles disperse linearly. The resulting BFC and excitations around it leave a distinct $T^2$ temperature dependence in their contribution to specific heat. Furthermore, the topologically protected BFC being a Majorana Fermi surface gives rise to a zero-bias peak the strength of which characteristically depends on the length of Fermi arc and tunneling strength. For the other BC that flips the chirality at the interface, instead of BFCs we have Bogoliubov- Weyl nodes whose location depends on the tunneling strength.