# Double Andreev Reflections in Type-II Weyl Semimetal-Superconductor Junctions

## TL;DR

This paper investigates double Andreev reflections in type-II Weyl semimetal-superconductor junctions, revealing anisotropic conductance and novel reflection phenomena due to the hyperboloidal Fermi surface near Weyl nodes.

## Contribution

It introduces the concept of double Andreev reflections in type-II Weyl semimetal-superconductor interfaces, highlighting their dependence on interface orientation and energy, which was not previously understood.

## Key findings

- Double ARs occur when superconductor aligns with Weyl band tilting.
- Double ARs evolve with interface orientation, showing various reflection types.
- Anisotropic conductance can be experimentally observed.

## Abstract

We study the Andreev reflections (ARs) at the interface of the type-II Weyl semimetal-superconductor junctions and find double ARs when the superconductor is put in the Weyl semimetal band tilting direction, which is similar to the double reflections of light in anisotropic crystals. The directions of the double (retro and specular) ARs are symmetric about the normal due to the hyperboloidal Fermi surface near the Weyl nodes, but with different AR amplitudes depending on the direction and energy of the incident electron. When the normal direction of the Weyl semimetal-superconductor interface is changed from parallel to perpendicular with the tilt direction, the double ARs gradually evolve from one retro-AR and one specular AR, passing through double retro-ARs, one specular AR and one retro-AR, into one retro AR and one normal reflection, resulting in an anisotropic conductance which can be observed in experiments.