Weyl-Majorana solenoid

TL;DR

This paper studies a Weyl semimetal wire with surface states that, when covered with a superconductor, host Majorana modes, revealing how superconducting coupling influences topological surface states and Majorana fermion trapping.

Contribution

It demonstrates how superconducting coverage transforms Fermi arcs into Majorana modes and shows Majorana trapping via gap inversion along the wire.

Findings

Coupling to superconductor breaks Fermi arcs into Majorana modes.

Variation in coupling strength causes gap inversion and Majorana trapping.

Surface states are topologically transformed by superconducting proximity.

Abstract

A Weyl semimetal wire with an axial magnetization has metallic surface states (Fermi arcs) winding along its perimeter, connecting bulk Weyl cones of opposite topological charge (Berry curvature). We investigate what happens to this "Weyl solenoid" if the wire is covered with a superconductor, by determining the dispersion relation of the surface modes propagating along the wire. Coupling to the superconductor breaks up the Fermi arc into a pair of Majorana modes, separated by an energy gap. Upon variation of the coupling strength along the wire there is a gap inversion that traps the Majorana fermions.